Hot Topics at Photonics West - SPIE

2014 Hot Topics at Photonics West

8928-81, The brain activity map: imaging the activity of entire neural circuits; Rafael Yuste (Columbia Univ.) 1-Feb-14, 8:30 AM In physical systems built with many components, emergent properties, such as magnetism, are often generated from the interactions among these particles. These emergent properties are often invisible when observing individual particles, since they depend on large-scale interactions between them. Likewise, the function of the brain has been mostly studied by examining the responses of individual neuron, yet it is probably an emergent property that arises from the coordinated activity of large numbers of neurons in each of its neural circuits. To capture this emergent level of brain function, we have launched a large-scale, international public project, the Brain Activity Map Project (or BRAIN Initiative), aimed at developing new methods to measure and control neural activity across complete neural circuits in experimental animals and human patients. This technological effort will be an interdisciplinary project, incorporating into neuroscience many methods and approaches from the physical sciences and nanotechnologies. The data obtained with these new methods could prove to be an invaluable step towards understanding fundamental and pathological brain processes. Finally, the novel technologies developed by this project, like it happened with the Human Genome Project, could give rise to new areas of economic and industrial development. 8931-2, Drug resistance mechanisms, photodynamic therapy (PDT) and combination treatment; Tayyaba Hasan (Massachusetts General Hospital) 1-Feb-14, 9:25 AM Resistance of cancer cells to treatment, be inherent or acquired, is multifactorial and may be viewed in two broad categories. The first arises from alterations within cancer cells that inhibit the action of drugs through a variety of mechanisms such as enhanced drug efflux or inhibition of cellular repair machinery. The second originates in alterations (increase or decrease) of signaling pathways that regulate cell growth and proliferation where there is also a possibility of cross talk, thus creating additional challenges in the destruction of cancer cells. Photodynamic therapy may have a specific role in ameliorating drug resistance mechanisms by the targeted destruction of such specific pathways. A combination of mechanistic understanding and creative chemistry to achieve multiagent delivery or other methods to inhibit several pathways and activate death mechanisms has the potential to enhance tumor control. Recent results on the use of such delivery constructs and approaches for PDT and their implications will be presented. 8931-4, Combination of photodynamic therapy and cancer molecular targeted agents; Bin Chen (Univ. of the Sciences in Philadelphia) 1-Feb-14, 10:05 AM Photodynamic therapy (PDT) induces cell damage and even cell death through the generation of reactive oxygen species (ROS). Depending on the type of cells, photosensitizer and light doses, PDT has been shown to induce cell apoptosis, necrosis and autophagy. PDT is also known to activate cell survival pathways. The final PDT outcome is dependent on the interplay between PDT-induced cell death and survival signals. To enhance the therapeutic outcome of PDT, it is necessary to further potentiate PDT-induced death signal and/or inhibit PDT-induced survival signal.


8938-11, Dual optical coherence tomography and infrared thermography imaging system; Israel Gannot (Tel Aviv Univ.) 1-Feb-14, 1:30 PM Multimodal imaging systems offer a more comprehensive view of a tissue, revealing its physical structure as well as its functionality. Different pathologies can induce functional changes, such as endogenous heat sources (inflammatory regions), and structural changes which generate refractive index mismatch. This work presents a bimodal imaging system consisting of an optical coherence tomography (OCT) and thermography modalities. A thermal camera was used to measure surface temperature variability and detect internal heat sources. A swept source full field OCT was implemented, in order to image tissue's structural changes. The integrated system produces co-registered thermal and cross-section images. 8958-7, An ultrawide-angle artificial reflecting superposition compound eye; John Rogers (Univ. of Illinois at Urbana-Champaign), Chi-Chieh Huang (Univ. of Wisconsin-Madison), Hongrui Jiang (Univ. of Wisconsin-Madison), Hewei Liu (Univ. of Wisconsin-Madison) 1-Feb-14, 2:00 PM We present a set of materials, modeling, manufacturing approaches and characterization schemes to realize a life-sized, ultra-wide-angle artificial RSCEs as optical imaging devices suitable for the visible wavelengths inspired by their natural counterparts. Such devices, fabricated by a peeling micro-transfer printing method, can form real, erect images based on reflection without any post-image processing and achieve optical features such as 165-degree field of view, minimum chromatic aberration, fine image quality and enhanced sensitivity to light and motion. In general, our work points to new directions in implementing biological optics into advanced photonic applications in military, security, medical imaging and astronomy. 8958-9, Bio-inspired hemispherical compound eye camera; Kenneth Crozier (Harvard Univ.), Yonggang Huang (Northwestern Univ.), Jianliang Xiao (Univ. of Colorado Boulder), Young Min Song (Univ. of Illinois at Urbana-Champaign), Yizhu Xie (Univ. of Illinois at Urbana-Champaign), Viktor Malyarchuk (Univ. of Illinois at Urbana-Champaign), John Rogers (Univ. of Illinois at Urbana-Champaign) 1-Feb-14, 2:40 PM Compound eyes in arthropods demonstrate distinct imaging characteristics from human eyes, with wide angle field of view, low aberrations, high acuity to motion and infinite depth of field. Artificial imaging systems with similar geometries and properties are of great interest for many applications. However, the established planar sensor technologies and conventional optics cannot meet the challenges in building such systems. We present our recent progress in combining optics, materials, mechanics and integration schemes to build fully functional artificial compound eye cameras. Nearly full hemispherical shapes with densely packed artificial ommatidia were realized.


8932-17, Can light interact with neurons to decrease pain?; Marcelo Pires de Sousa (Univ. de São Paulo), Elisabeth Yoshimura (Univ. de São Paulo), Michael Hamblin (Wellman Ctr. for Photomedicine), Cleber Ferraresi (Wellman Ctr. for Photomedicine), Beatriz Kaippert (Wellman Ctr. for Photomedicine), Masayoshi Kawakubo (Wellman Ctr. for Photomedicine) 1-Feb-14, 3:50 PM The incidences of chronic and acute pain are rising. Several studies have demonstrated the effectiveness of low-level laser (light) therapy (LLLT) to decrease many types of pain in different body locations, but the mechanisms for the pain relieving effect are still not clear. We carried a search for these mechanisms using a mouse model of measuring pain threshold employing von Frey filaments. Doing so, we have found new ways of treating and have found strong evidence for the direct interaction of light with neurons as the major cause of pain attenuation. 8926-20, Optical treatment strategies for unsolved skin problems: pros, cons, and some whacky ideas; R. Rox Anderson (Massachusetts General Hospital) 2-Feb-14, 8:30 AM The optical toolbox for skin treatment includes UV phototherapy, light-activated drugs, surgical lasers, flashlamps, optical nanoparticles and so-called low level light sources. We also have some remarkably interesting in vivo microscopes and optical diagnostics. These and others were motivated for treatment of a handful of the appropriately 2000 skin diseases. A few have provided miracle cures, many are useful but could use major improvement, and some just don't work well enough to be useful. Taking a problem-driven approach, in view of known mechanisms and capabilities in our optical toolbox - where might we make some strides? 8939-20, A pilot study on Raman mapping of normal and cancerous oral tissues; Singaravelu Ganesan (Anna Univ. Chennai), Amuthachelvi Daniel (Anna Univ. Chennai), Aruna Prakasa Rao (Anna Univ. Chennai), Balu David M. (Arignar Anna Memorial Cancer Hospital & Research Institute), Dornadula Koteeswaran (Meenakshi Ammal Dental College & Hospital), S. Jayachandran (Tamil Nadu Government Dental College & Hospital) 2-Feb-14, 10:30 AM Raman spectroscopy has shown significant potential in the characterization and clinical diagnosis of normal and cancerous tissues. Five normal oral tissues and three oral cancer tissues were mapped using MicroRaman Confocal system. Considerable differences between the noncancerous and cancerous oral tissues were found in vibrational characteristics of carotenoids, fatty acids and proteins. Following Raman mapping, the tissue sections were stained for histopathological analysis, enabling identification of the histological origin of the Raman signature and assignment of the Raman spectral clusters to different regions of the mapped tissue. 8933-21, Smart-phone based albumin testing in urine; Ahmet Coskun (California Institute of Technology), Aydogan Ozcan (Univ. of California, Los Angeles), Stephen Phillips (Univ. of California, Los Angeles), Richie Nagi (Univ. of California, Los Angeles), Kayvon Sadeghi (Univ. of California, Los Angeles) 2-Feb-14, 11:00 AM We introduce a field-portable sensing platform, termed Albumin Tester, running on a smart-phone that images and automatically analyses fluorescent assays for sensitive and specific detection of albumin in urine. Through the use of an add-on module attached to the cellphone, test and control tubes are excited using a laser diode. Capturing the fluorescent images of these tubes through the cellphone camera, the raw images are rapidly processed using an Android application running on the same cellphone. This Albumin Tester, achieving 5-10ug/mL detection limit within ~5 min per test, could impact early diagnosis of kidney diseases or monitoring of chronic patients.


8948-9, Towards a compact fiber laser for multimodal imaging; Hui Liu (Cornell Univ.), Andy Chong (Cornell Univ.), Frank Wise (Cornell Univ.), Sergey Arkhipov (Michigan State Univ.), Marcos Dantus (Michigan State Univ.), Ilyas Saytashev (Michigan State Univ.), Bai Nie (Michigan State Univ.) 2-Feb-14, 11:50 AM Nonlinear optical microscopy with sub-30 fs pulses from an Yb fiber oscillator, approximately three times shorter than typical fiber laser pulse duration, leads to order of magnitude brighter third harmonic generation images. Multiphoton fluorescence, second and third harmonic generation modalities are compared on stained microspheres and unstained biological tissues including guppy fish (Poecilia reticulata) tails and fruit fly (Drosophila melanogaster) wings. 8926-37, Using infrared imaging polarization imaging to detect skin cancer; Joseph Peller (The Univ. of North Carolina at Charlotte), Susan Trammell (The Univ. of North Carolina at Charlotte) 2-Feb-14, 4:00 PM We are investigating the ability of polarization measurements at thermal infrared (9-10 microns) wavelengths to detect skin cancer. Thermal emission originates in the superficial layers of skin where cancer develops and polarization measurements of this emission can characterize the properties of these layers. We have measured the degree of linear polarization from thermal emission of porcine skin samples both before and after the creation of thermal lesions on the tissue. After thermal damage, a clearly defined area of lower polarization was evident. These preliminary results indicate that our imaging technique could be used to detect abnormalities associated with skin cancer. 8930-44, Compact adaptive optics line scanning retinal imager: closer to the clinic; R. Daniel Ferguson (Physical Sciences Inc.), Mircea Mujat (Physical Sciences Inc.), Ankit Patel (Physical Sciences Inc.), Nicusor Iftimia (Physical Sciences Inc.) 2-Feb-14, 4:30 PM The performance of clinical confocal SLO and OCT imagers is limited by ocular aberrations. Adaptive optics (AO) addresses this problem, but most research systems are large, complex, and less well suited to the clinical environment. PSI's recently developed compact retinal imager is designed for rapid, automated generation of cone photoreceptor density maps. The device has a compact foot-print suitable for clinical deployment. The system previously presented at Photonics West has been upgraded to include numerous new features that support clinical research applications. These upgrades significantly enhance the capabilities of the imager, providing the clinician with simultaneously-acquired (registered) en face photoreceptor images and AO-OCT retinal cross-sections. We present a detailed discussion of these new features. 8926-41, Hyperspectral imaging for melanoma screening; Daniel Gareau (The Rockefeller Univ.), James Krueger (The Rockefeller Univ.), Justin Martin (The Rockefeller Univ.) 2-Feb-14, 5:20 PM The 5-year survival rate for patients diagnosed with late-stage Melanoma about 15%, compared to over 90% for early detection. We present an imaging system and algorithm that automatically generates a melanoma risk score to aid early detection. Our system images at a series of wavelengths and then analyzes key dermoscopic features to generate this risk score. Shorter wavelengths of UVA light are sensitive to information in the superficial areas of the skin while longer wavelengths gather information at greater depths. This system has demonstrated much higher sensitivity and specificity than the currently commercialized system in this preliminary clinical trial.


8935-75, Assessment of metastatic disease in human lymph nodes via intraoperative optical coherence tomography; Andrew Cittadine (AdvancedMEMS), Donald Darga (AdvancedMEMS), Daniel McCormick (AdvancedMEMS), George Liu (Carle Foundation Hospital), Partha Ray (Carle Foundation Hospital), Kimberly Cradock (Carle Foundation Hospital), John Brockenbrough (Carle Foundation Hospital), Jeffrey Putney (Diagnostic Photonics, Inc.), Paul Carney (Univ. of Illinois at Urbana-Champaign), Stephen Boppart (Univ. of Illinois at Urbana-Champaign), Douglas Simpson (Univ. of Illinois at Urbana-Champaign), Ryan Shelton (Univ. of Illinois at Urbana-Champaign), Andrew Bower (Univ. of Illinois at Urbana-Champaign), Marina Marjanovic (Univ. of Illinois at Urbana-Champaign), Eric Chaney (Univ. of Illinois at Urbana-Champaign), Nathan Shemonski (Univ. of Illinois at Urbana-Champaign), Guillermo Monroy (Univ. of Illinois at Urbana-Champaign), Fredrick South (Univ. of Illinois at Urbana-Champaign), Sarah Erickson-Bhatt (Univ. of Illinois at Urbana-Champaign), Steven Adie (Univ. of Illinois at Urbana-Champaign), Ryan Nolan (Univ. of Illinois at Urbana-Champaign) 2-Feb-14, 5:30 PM Lymph node assessment is essential for staging cancer since primary tumor cells often metastasize via the lymphatic system. Currently, lymph nodes are assessed by sentinel lymph node biopsy and time-consuming post-operative histopathological analysis. Our double-blinded study of three-dimensional optical coherence tomography (OCT) intraoperative assessment of lymph nodes compared to histopathology evaluates the sensitivity and specificity of the majority vote for each lymph node from our readers’ diagnosis. Additionally, in situ and ex vivo assessment of lymph nodes with our handheld OCT surgical probe could potentially reduce the risk of lymphedema by decreasing the number of normal lymph nodes removed. 8947-13, Beat frequency-multiplexed fluorescence lifetime measurements for high-speed confocal lifetime microscopy; Eric Diebold (Univ. of California, Los Angeles), Brandon Buckley (Univ. of California, Los Angeles), Jacky Chan (Univ. of California, Los Angeles), Sien Mao (Univ. of California, Los Angeles), Najva Akbari (Univ. of California, Los Angeles), Bahram Jalali (Univ. of California, Los Angeles) 3-Feb-14, 2:00 PM We report a novel, low cost and highly tunable optical system for real-time lifetime measurements. Deemed lifetime imaging using frequency-multiplexed excitation (LIFE), a digitally-synthesized signal is used to drive an acousto-optic deflector, which is operated in a cat’s eye configuration to produce a single laser excitation beam containing multiple beat frequencies in the MHz range. As validation, we demonstrate phase measurements for selected lifetime standards that are probed simultaneously using ten distinct frequencies over a bandwidth of 48 MHz. 8935-39, Implementation and evaluation of Google Glass for visualizing real-time image and patient data in the primary care office; Stephen Boppart (Univ. of Illinois at Urbana-Champaign), Nathan Shemonski (Univ. of Illinois at Urbana-Champaign), Guillermo Monroy (Univ. of Illinois at Urbana-Champaign), Ryan Shelton (Univ. of Illinois at Urbana-Champaign), Ryan Nolan (Univ. of Illinois at Urbana-Champaign) 3-Feb-14, 5:00 PM Primary care physicians must conduct a staggering number of comprehensive physical exams and medical record reviews, resulting in demanding daily schedules. Few commercial technologies have been marketed towards primary care, which has stifled improvements in disease screening and detection, work flow, records management, and interaction with patients. In efforts to improve the quality of care in primary care medicine, we integrated our handheld optical imaging system with Google Glass©, a commercial heads-up display (HUD). The integration of a HUD allows the physician to focus on the patient, resulting in increased quality of care and efficient, real-time data display and analysis.


8935-51, System for clinical photometric stereo endoscopy; Norman Nishioka (Massachusetts General Hospital), Benjamin Vakoc (Massachusetts General Hospital), Vicente Parot (Massachusetts Institute of Technology), Daryl Lim (Massachusetts Institute of Technology), German Gonzalez (Massachusetts Institute of Technology), Nicholas Durr (Massachusetts Institute of Technology), Giovanni Traverso (Massachusetts Institute of Technology) 4-Feb-14, 1:50 PM Photometric Stereo Endoscopy (PSE) is a novel technique that obtains information about the high-spatial-frequency topology of the field of view simultaneously with the conventional color image. In this work, we describe the principles of PSE, progress on our development of a PSE system for human clinical testing, and solutions to visualize PSE contrast. Our clinical PSE endoscope has the same outer diameter as a conventional colonoscope, plugs in to a commercial video processor, captures PSE images at 15 Hz, and displays a conventional color movie to the gastroenterologist. Using this system, we show topographical reconstructions of ex-vivo human colon tissue. 8935-62, Minimal resection approaches for lung cancer surgery using intraoperative merged fluorescence imaging system; Yuhua Quan (Korea Univ.), Hyun Koo Kim (Korea Univ.), Beop-Min Kim (Korea Univ. College of Health Sciences), Yujin Oh (Korea Univ. College of Health Sciences) 4-Feb-14, 5:50 PM Intraoperative Near infrared (NIR) fluorescence imaging system has been developed for operating minimal resection lung cancer surgery. We conducted preclinical segmentectomy using indocyanine green (ICG). It was found that intersegmental plane was identified clearly through the contrast of the fluorescence signal. We are preparing for clinical translation for human segemtectomy study in the near future. 8947-35, Ultrahigh-throughput imaging flow cytometry using radiofrequency-tagged emission; Eric Diebold (Univ. of California, Los Angeles), Brandon Buckley (Univ. of California, Los Angeles), Bahram Jalali (Univ. of California, Los Angeles) 5-Feb-14, 8:00 AM We present a high-speed fluorescence microscopy modality, which is inspired by the field of radiofrequency communication. Deemed fluorescence imaging using radiofrequency-tagged emission (FIRE), this approach maps the image into the radiofrequency spectrum using the beating of digitally synthesized optical fields. We demonstrate diffraction-limited confocal fluorescence imaging of cells at a frame rate of 4.4 kHz, as well as fluorescence imaging of cells in flow at velocities greater than 1 m/s. This velocity corresponds to a throughput of approximately 50, 000 cells per second, which represents an order of magnitude improvement over the current state-of-the-art in fluorescence imaging flow cytometry. 8940-34, Supercontinuum generation in optical fibers and its biomedical applications; Govind Agrawal (Univ. of Rochester) 5-Feb-14, 2:30 PM A microstructured optical fiber was first used in 2000 for supercontinuum generation. Since then, enormous progress has been made in understanding, controlling, and marketing fiber-based supercontinuum sources. In particular, biomedical applications of such sources are revolutionizing the field of medical imaging. In this talk I review the recent progress in this area and describe how a supercontinuum can be employed for biomedical imaging using the techniques known as coherent anti-Stokes Raman scattering, stimulated emission-depletion microscopy, and optical coherence tomography.


8961-2, Single-frequency Yb-doped photonic crystal fiber amplifier with 800 W output power; Iyad Dajani (Air Force Research Lab.), Craig Robin (Air Force Research Lab.) 3-Feb-14, 9:10 AM A novel acoustic and gain tailored Yb-doped photonic crystal fiber is used to demonstrate over 800 W single-frequency output power with near diffraction limited beam quality at 1064 nm. The large mode area fiber core is composed of 7 individually doped segments arranged to create three distinct acoustic regions and preferential gain overlap with the fundamental optical mode. 8960-4, Kerr comb generation from the perspective of spatial dissipative structures; Yanne Chembo (FEMTO-ST), Aurélien Coillet (FEMTO-ST), Khaldoun Saleh (FEMTO-ST), Irina Balakireva (FEMTO-ST), Rémi Henriet (FEMTO-ST), Laurent Larger (FEMTO-ST) 3-Feb-14, 9:15 AM We investigate the formation of dissipative structures leading to Kerr comb generation in crystalline whispering-gallery mode disk resonators that are pumped in different dispersion regimes. We show how bright or dark cavity solitons can emerge, and we use the Lugiato-Lefever spatiotemporal formalism to investigate the temporal dynamics leading to the formation of azimuthal solitons and Turing patterns. The theoretical results are in excellent agreement with experimental measurements. 8969-15, Optical and electronic properties of transition metal dichalogenides at monolayer thickness; Tony Heinz (Columbia Univ.) 3-Feb-14, 2:00 PM MoS2 is a prototype of a family of atomically thin metal dichalcogenides. Although the structure of the monolayer is similar to that of graphene, the A and B sublattice are occupied either by Mo atoms or by a pair of S atoms, rather than by C atoms. This difference in symmetry allows MoS2to be a semiconductor with a significant band gap. Through characterization of the optical properties of the material as a function of thickness, we show that quantum confinement effects lead to a crossover in MoS2 from a dark, indirect-gap semiconductor in the bulk to a bright, direct-gap semiconductor at monolayer thickness [1]. As is common for lower-dimensional materials, excitonic effects are also very strong in MoS2 as we demonstrate through the spectroscopic identification of charged excitons (trions) [2]. Another distinctive feature of this material is the possibility of producing long-lived valley polarization by excitation with circularly polarized light [3], as we show through photoluminescence measurements [3]. [1] K. F. Mak et al., Phys. Rev. Lett. 105, 136805 (2010). [2] K. F. Mak et al., Nature Mater. 12, 207–211 (2013). [3] K. F. Mak et al., Nature Nanotech. 7, 494-498 (2012). 8963-1, Laser welding of XXL structures; Stefan Kaierle (Laser Zentrum Hannover e.V.), André Springer (Laser Zentrum Hannover e.V.), Oliver Seffer (Laser Zentrum Hannover e.V.), Rabi Lahdo (Laser Zentrum Hannover e.V.), Alexander Barroi (Laser Zentrum Hannover e.V.), Jörg Hermsdorf (Laser Zentrum Hannover e.V.) 4-Feb-14, 8:20 AM In the last 50 years laser material processing has successfully been established, especially in the area of thin materials. With the availability of more powerful laser sources it is now possible to process larger


dimensions. The combination of a laser process with one or two GMA sub-processes to a hybrid welding process provides an application of brilliant laser radiation for conventional welding practices because of the increased gap bridgeability. Thus, material thicknesses up to 23 mm of steel grade X70 for pipeline applications are joined in flat position within a single process step over the whole thickness with a speed of about 1.5 m/min. For this purpose, a high-power disc laser source is used with a maximum output power of 16 kW. For plates of the aluminum alloy EN AW-6082-T6 with a thickness of 12 mm speeds of up to 6 m/min were used. By the use of an additional inductive preheating for welding of fine-grain structural steels with the grades S700MC, X70 and S690QL in a thickness range from 10 to 15 mm, it is possible to increase the welding speed and to obtain homogeneous mechanical properties near the welding seam. Other examined applications are the welding of large steel-aluminum foam sandwiches for shipbuilding and the high-rate deposition-welding process with a none-transferred arc which burns between two wire electrodes. For the latter, the laser is used to control the welding penetration in order to combine the high deposition rates of the arc process of up to 20 kg/h with a low heat input into the workpiece. In all the mentioned areas, with more applications being investigated, the laser offers the possibility to produce high quality joints at high speeds. 8963-6, Trends and basic investigations in high power laser materials processing; David Havrilla (TRUMPF Inc.), Patrick Haug (TRUMPF Laser- und Systemtechnik GmbH), Volker Rominger (TRUMPF Laser- und Systemtechnik GmbH), Thomas Harrer (TRUMPF Laser- und Systemtechnik GmbH), Marco Holzer (TRUMPF Laser- und Systemtechnik GmbH) 4-Feb-14, 10:40 AM Continuous application development in combination with advancements in laser sources and accessories enabled several trends in laser material processing. This paper will show investigations in process understandings based on modern process diagnostics like high speed videos. We will focus on applications related to thick sheet welding, welding with wobbling techniques, hot-forming materials and dissimilar materials. Additionally we link the gained process understandings to possibilities how to successfully introduce the knowledge in industrial applications. 8961-30, 3kW single-mode direct diode-pumped fiber laser; John Minelly (Coherent, Inc.), Richard Tumminelli (Coherent, Inc.), Vincent Petit (Coherent, Inc.), Eric Pooler (Coherent, Inc.), Victor Khitrov (Coherent, Inc.) 4-Feb-14, 3:30 PM We present a 3kW single-mode fiber laser based on an Yb-doped LMA fiber operating at 1080nm. The laser which is pumped by 9xxnm diode bars stacks is believed to be the highest power direct diode pumped single-mode fiber laser oscillator to date. 8963-17, Lasers for welding and their potential in production at GE; Marshall Jones (GE Global Research) 5-Feb-14, 2:00 PM Laser technology has been used in manufacturing in industry since the late 1960s. Industry and GE businesses have leverage laser welding for productivity gains, cost savings, and quality. The presentation will high-lights several laser-based welding applications, old and new. Applications will include the welding of refractory materials (e.g. Mo and Nb) for lighting products; 40 foot long fuel rods are welded with 2 kW fiber lasers for the nuclear business; head-liner welding for the diesel engine for locomotives (14 kW fiber laser replaced CO2 laser); and X-ray components are welded in a two-station 11kW fiber laser (EB welding replaced by laser). The three fiber laser applications were all transitioned into GE businesses during 2011 and it demonstrates the emergence of fiber laser welding being used in GE for manufacturing.


8961-48, 2.1mJ, 210W femtosecond fiber CPA system; Armin Hoffmann (Friedrich-Schiller-Univ. Jena), Steffen Hädrich (Friedrich-Schiller-Univ. Jena), Tino Eidam (Friedrich-Schiller-Univ. Jena), Thomas Gottschall (Friedrich-Schiller-Univ. Jena), Jens Limpert (Friedrich-Schiller-Univ. Jena), Andreas Tünnermann (Friedrich-Schiller-Univ. Jena), Arno Klenke (Friedrich-Schiller-Univ. Jena) 6-Feb-14, 8:00 AM Coherent combination offers a way to overcome limitations of single laser amplifiers. We report on a femtosecond fiber laser system based on this approach in conjunction with the chirped-pulse amplification (CPA) technology. The main amplification stage is based on four large-pitch fiber (LPF) amplifiers in a parallel configuration. The combination and stabilization is realized using the polarization combination approach with an active Hänsch- Couillaud stabilization system. With these components, we could achieve a combined average power of 210 W at a repetition rate of 100 kHz. This corresponds to a pulse energy of 2.1 mJ. 8968-16, Control of multiphoton and avalanche ionization using an ultraviolet-infrared pulse train in femtosecond laser micro/ nano-machining of fused silica; Zenghu Chang (CREOL, The College of Optics and Photonics, Univ. of Central Florida), Shuting Lei (Kansas State Univ.), Xiaoming Yu (Kansas State Univ.), Qiumei Bian (Kansas State Univ.), Paul Corkum (National Research Council Canada) 6-Feb-14, 8:30 AM We report on the experimental results of microstructures fabricated on the surface of fused silica by a train of two femtosecond laser pulses, a tightly focused 266 nm (ultraviolet, UV) pulse followed by a loosely focused 800 nm (infrared, IR) pulse. Structures with dimensions of ~200 nm can be fabricated on the surface of fused silica by this technique with UV energy density below its single beam damage threshold using a high numerical aperture (NA) objective. 8961-62, Threshold power and fiber-degradation-induced modal instabilities in high-power fiber amplifiers based on large-mode-area fibers; Khushvinder Brar (Lockheed Martin Laser and Sensor Systems), Jason Henrie (Lockheed Martin Laser and Sensor Systems), Sean Courtney (Lockheed Martin Laser and Sensor Systems), Matthias Savage-Leuchs (Lockheed Martin Laser and Sensor Systems), Robert Afzal (Lockheed Martin Laser and Sensor Systems), Eric Honea (Lockheed Martin Laser and Sensor Systems) 6-Feb-14, 3:40 PM We report on modal instabilities observed in high power Yb amplifiers based on Large Mode Area Fibers. We observe both Threshold Power Modal Instabilities (TPMI) and Fiber Degradation Modal Instabilities (FDMI). Experiments on degraded fiber show a wavelength dependent permanent change is created in the degraded fiber with a memory of the original operating wavelength. We propose a simple picture where modal interference periodically mediates photodarkening or other defect formation in the fiber material creating a grating structure that can then couple the fundamental mode to higher order modes at high thermal loading.


8978-2, Focus-tunable Moiré lenses from stacked diffractive optical elements; Stefan Bernet (Innsbruck Medical Univ.), Monika Ritsch-Marte (Innsbruck Medical Univ.), Walter Harm (Innsbruck Medical Univ.) 2-Feb-14, 8:20 AM We have experimentally assessed the performance of high efficiency focus-tunable lenses consisting of a pair of diffractive optical elements (DOEs) fabricated in 0.75 mm thick glass slides. Due to the Moiré effect the transmission function of the combined DOEs corresponds to that of a Fresnel zone lens. However, in our case the refractive power of the stacked element can be continuously tuned by a mutual rotation of the DOEs around their central axis. We demonstrate applications of these flat zoom lenses in imaging and beam steering. 8978-5, MEMS and the direct detection of exoplanets; Sandrine Thomas (NASA Ames Research Ctr.) 2-Feb-14, 9:20 AM Deformable mirrors (DMs) are crucial components for exoplanets’ direct imaging using coronagraph. Real systems’ performance is always limited by image quality degradation resulting from dynamic and static wavefront errors. Correcting for these effects necessitate DMs with fast response, numerous actuators and moderate stroke, requirements that MEMs devices fulfill. In this paper, I will discuss coronagraphs requirements for extremely high Strehl ratios as well as the different control loops required to produce extremely high contrast images. As examples, I will discuss results from two different projects: the Gemini Planet Imager and the Nasa Ames Coronagraph Experiment laboratory testbed. 8978-14, Adaptive optics for superresolution nanoscopy; Fiona Kenny (Univ of Oxford), Brian Patton (Univ. of Oxford), Daniel Burke (Univ. of Oxford), Maria Frade Rodriguez (Univ. of Oxford), Martin Booth (Univ. of Oxford) 2-Feb-14, 3:30 PM Superresolution microscopes (STED, RESOLFT, PALM, STORM, GSDIM, etc.) resolve features on the scale of tens of nanometers and lower. However, these microscopes all suffer from the effects of aberrations that compromise resolution, signal and image quality. We present methods for the adaptive compensation of aberrations in 2D and 3D STED microscopes through image-based sensorless adaptive optics. Similar methods are implemented in single molecule switching microscopes. 3D enhanced superresolution images are taken through thick aberrating biological specimens. The significant improvement in image quality through adaptive optics will aid the application of superresolution methods in a wider range of biologically relevant specimens.


8976-16, Laser patterning for paper-based fluidics; Matthias Feinaeugle (Univ of Southampton, Optoelectronics Research Centre), Ben Mills (Univ. of Southampton), Robert Eason (Univ. of Southampton), Collin Sones (Univ. of Southampton), Ioannis Katis (Univ. of Southampton), Medya Namiq (Univ. of Southampton), Morten Ibsen (Univ. of Southampton) 2-Feb-14, 4:30 PM Paper-based microfluidics is a rapidly progressing inter-disciplinary technology driven by the need for low-cost alternatives to conventional point-of-care diagnostic tools. For transport of reagents/analytes, such devices often consist of interconnected hydrophilic fluid-flow channels that are demarcated by hydrophobic barrier walls that extend through the thickness of the paper. Here, we present a laser-based fabrication procedure that uses photo-polymerisation of a negative hydrophobic photoresist in order to produce the required fluidic channels in paper. Analysis showed that the structures directed the flow of water and hence the technique is suited for fabrication of microfluidic devices. 8974-1, Liquid deposition photolithography for the fabrication of three dimensional gradient index micro-optics; Robert McLeod (Univ. of Colorado at Boulder), Adam Urness (Univ. of Colorado at Boulder), Michael Cole (Univ. of Colorado at Boulder) 3-Feb-14, 1:30 PM Diffusive (also known as holographic) photopolymers are optically exposed to create self-developing 3D refractive index structures but lack complete 3D control due to diffraction and the diffusion time for large features. We present a fabrication method and photopolymer formulation that can efficiently create multi-cubic mm optical devices with programmable, gradient index of refraction with arbitrary feature size and shape. We demonstrate index contrast of 0.1 and transverse feature size ranging from 150 nm to 6 mm and axial feature size ranging from 1 micron to 10 mm. We demonstrate the process by fabricating thick waveguide arrays and gradient index lenses. 8975-4, MEMS tactile display: from fabrication to characterization; Hiroaki Ishikawa (Keio Univ), Junpei Watanabe (Keio Univ), Norihisa Miki (Keio Univ.), Yumi Kosemura (Keio Univ.) 3-Feb-14, 2:40 PM We report fabrication and characterization of MEMS-based tactile display that can display users various tactile information, such as Braille codes and surface textures. The display consists of 9 micro-actuators that are equipped with hydraulic displacement amplification mechanism (HDAM). We developed a liquid encapsulation process, Bonding-in-Liquid Technique, to manufacture the HDAM. The micro-actuators were characterized and could successfully stimulate the tactile receptors in our fingertips. However, same output of the display does not necessarily provide same tactile feeling to different users. Therefore, we introduced a sample comparison method to characterize the system that involves the display and users. 8977-1, MEMS endoscopes for advanced biomedical imaging; Ki-Hun Jeong (KAIST), Hyeon-Cheol Park (KAIST), Kyungwon Jang (KAIST) 3-Feb-14, 3:30 PM Advanced biomedical imaging techniques are of much interest in clinical applications such as optical biopsy or imaging guided surgery. Miniaturization of imaging system is still challenging and under development for endoscopic applications due to tough spatial and operational restrictions. Recently, MEMS provides a sole solution for the system compactness with high speeds under clinical safe operations. In this work, we will introduce some recent development of MEMS enabled endoscopes for forward endoscopic imaging. The MEMS lens scanner, which consist of two commercial aspheric glass lenses laterally mounted on two resonating electrostatic MEMS scanner, has been fully packaged and combined with 3D SD-OCT system. 3D stereoscopic imaging endoscope was also demonstrated by


rotating a thin transparent plate in front of a single camera with bimorph MEMS actuator. A novel combination of MEMS and advanced optical imaging modalities will provide new directions for advanced endoscopic diagnosis. 8975-6, Characterization of gallium nitride microsystems within radiation and high-temperature environments; Heather Chiamori (Stanford Univ.), Minmin Hou (Stanford Univ.), Caitlin Chapin (Stanford Univ.), Ashwin Shankar (Stanford Univ.), Debbie Senesky (Stanford Univ.) 3-Feb-14, 3:40 PM New milestones in space exploration can be realized through the development of radiation-hardened, temperature-tolerant materials, sensors and electronics. This enables lightweight systems (reduced packaging requirements) with increased operation lifetimes. Gallium nitride (GaN) is a ceramic, semiconductor material that is stable within high-radiation, high-temperature and chemically corrosive environments. Recently, this material platform has been utilized to realize sensors and electronics for operation under extreme harsh conditions. These devices exploit the two-dimensional electron gas (2DEG) formed at the interface between AlGaN/GaN heterostructures, which is used as the material platform in high electron mobility transistors (HEMTs). In this presentation, a review of the advancements in GaN manufacturing technology such as the growth of epitaxially deposited thin films, micromachining techniques, nanostructure synthesis and high-temperature metallization is presented. In addition, the compelling results of fabricating and operating micro-scale GaN-based sensors within radiation environments and at elevated temperatures are shown. The presentation will close with future directions GaN-based microsystems technology for propulsion, space exploration and military applications. 8977-2, A high-resonance-frequency MEMS Fabry-Perot tunable filter with applications in high speed swept-source optical coherence tomography (OCT) imaging; Vaibhav Mathur (AXSUN Technologies Inc.), Peter Whitney (AXSUN Technologies Inc.), Mark Kuznetsov (AXSUN Technologies Inc.) 3-Feb-14, 4:00 PM No abstract. 8976-28, Pathology in a tube, step 1: fixing, staining, and transporting pancreatic core biopsies in a microfluidic device for 3D imaging; Greg Kramer (Nortis, Inc.), Eric Seibel (Univ. of Washington), Chris Burfeind (University of Washington), Ronnie Das (University of Washington) 3-Feb-14, 4:30 PM No abstract. 8975-13, Heterogeneous MEMS device assembly and integration; Patrice Topart (INO) 4-Feb-14, 8:00 AM This paper reports on the fabrication, assembly and packaging at INO of various MEMS devices using heterogeneous assembly at chip and package-level. First, the performance of a giant, electrostatically actuated beam steering-mirror is presented. The device results from fabrication and micro-asssembly from four separate wafers. Second, initial performance results of a device combining infrared detection and inertial sensing will be presented. Third, the hybrid integration of an uncooled bolometric detector with a CMOS read-out was employed to realize a broadband radiometer for the earthcare satellite. Finally, to simulate a 3072 pixel FPA for fire imaging, the staggered assembly of six, 512x3 pixel FPAs is described.


8976-39, Rapid detection tuberculosis using droplet-based microfluidics; Sindy Tang (Stanford Univ.), Liat Rosenfeld (Stanford University) 4-Feb-14, 11:50 AM No abstract. 8974-27, STED-inspired dip-in optical lithography of 3D chiral polarizers for visible and telecom wavelengths; Johannes Kaschke (Karlsruher Institut für Technologie), Martin Wegener (Karlsruher Institut für Technologie), Michael Thiel (Nanoscribe GmbH), Julian Ott (Nanoscribe GmbH), André Radke (Nanoscribe GmbH) 4-Feb-14, 4:20 PM We combine, for the first time, the concepts of dip-in and STED-inspired optical lithography to fabricate 3D nanostructures for photonics. For depletion of the photoinitiator ITX we employ a fiber-coupled laser diode at 639-nm wavelength. To demonstrate the performance of our STED-inspired dip-in lithography setup, we have fabricated 3D chiral polymeric twisted woodpile structures with 102 layers and with a lattice constant reduced by more than a factor of two compared to earlier results. The fabricated twisted woodpile structures serve as dual-band polarizers for circular polarization at visible and telecom wavelengths. Spectroscopic measurements agree well with scattering matrix calculations. 8979-23, Using DMDs for focusing light through turbid media; Wiendelt Steenbergen (Univ. Twente), Sri Nivas Chandrasekaran (Univ. Twente), Ivo Vellekoop (University of Twente), Hans Ligtenberg (University of Twente) 4-Feb-14, 5:00 PM The holy grail of biomedical optical imaging is to perform microscopy deep inside living tissue. Unfortunately, biological tissue scatters light, which prevents the formation of a sharp focus. However, recently it was shown that wavefront shaping can be used to focus light through and inside turbid materials. So far, most experiments used liquid crystal devices, which are too slow to match the dynamics of perfused tissue. Since DMD technology is 1000 times faster, it may bring wavefront shaping to in-vivo applications. We will demonstrate and compare algorithms for focusing light through scattering media with an intensity-only light modulator. 8974-49, One step lithography-less silicon nanomanufacturing for low cost, high-efficiency solar cell production; Yi Chen (Univ. of Illinois at Urbana-Champaign) 5-Feb-14, 8:30 AM To improve light absorption, previously various antireflection material layers were created on solar wafer surface including multilayer dielectric film, nanoparticle sludges, microtextures, noble metal plasmonic nanoparticles and 3D silicon nanostructure arrays. All of these approaches involve nanoscale prepatterning, surface-area-sensitive assembly processes or extreme fabrication conditions; therefore, they are often limited by the associated high cost and low yield as well as the consequent industry incompatibility. In comparison, our nanomanufacturing, an unique synchronized and simultaneous top-down and bottom-up nanofabrication approach called simultaneous plasma enhanced reactive ion synthesis and etching (SPERISE), offers a better antireflection solution along with the potential to increase p-n junction surface area. High density and high aspect ratio anechoic nanocone arrays are repeatedly and reliably created on the entire surface of single and poly crystalline silicon wafers as well as amorphous silicon thin films within 5 minutes under room temperature. The nanocone surface had lower than 5% reflection over the entire solar spectrum and a desirable omnidirectional absorption property. Using the nanotextured solar wafer, a 156mm × 156mm 18.1%-efficient black silicon solar cell was fabricated, which was an 18.3% enhancement over the cell fabricated by standard industrial


processes. This process also reduces silicon loss during the texturing step and enables tighter process control by creating more uniform surface structures. Considering all the above advantages, the demonstrated nanomanufacturing process can be readily translated into current industrial silicon solar cell fabrication lines to replace the costly and ineffective wet chemical texturing and antireflective coatings. 8977-3, Micro-scanning mirrors for high-power laser applications; Thilo Sandner (Fraunhofer-Institut für Photonische Mikrosysteme), Simon Kimme (Fraunhofer-Institut für Photonische Mikrosysteme), Thomas Grasshoff (Fraunhofer-Institut für Photonische Mikrosysteme), Ulrich Todt (Fraunhofer-Institut für Photonische Mikrosysteme), Harald Schenk (Fraunhofer-Institut für Photonische Mikrosysteme) 5-Feb-14, 1:00 PM Two novel micro scanners with large aperture and HR dielectric coatings suitable for high power laser applications are presented. An electrostatic driven 2D raster scanning mirror with 5x7.1mm aperture is used for dynamic steering of the ps-laser beam of the laser cutting process. A second magnetic 2D beam steering mirror enables a static beam correction of a hand guided laser instrument. Optimizations of a magnetic gimbal micromirror with 6mm x 8mm mirror plate are presented; here static deflections of 3° were reached. Both MEMS devices were successfully tested with a high power ps-laser at 532nm up to 20W CW. 8979-25, DMD-based reactive visual system design for programmable headlights; Srinivasa Narasimhan (Carnegie Mellon Univ.) 5-Feb-14, 1:00 PM The primary goal of a vehicular headlight is to improve safety in low-light and poor weather conditions. The typical headlight however has very limited flexibility - switching between high and low beams, turning off beams toward the opposing lane or rotating the beam as the vehicle turns - and is not designed for all driving environments. Thus, despite decades of innovation in light source technology, more than half of the vehicular accidents still happen at night even with much less traffic on the road. In this talk, I will describe a new DMD-based design for a headlight that can be programmed to perform several tasks simultaneously and that can sense, react and adapt quickly to any environment with the goal of increasing safety for all drivers on the road. For example, we will be able to drive with high-beams without glaring any other driver and we will be able to see better during rain and snowstorms when the road is most treacherous to drive. The headlights can also increase contrast of lanes, markings and sidewalks and can alert drivers to sudden obstacles. I will lay out the engineering challenges in building this headlight and share our experiences with the prototypes we developed over the past two years.


8977-6, Tunable external cavity quantum cascade lasers (EC-QCL) an application field for MOEMS-based scanning gratings; Michael Fontenot (Fraunhofer IPMS), Ralf Ostendorf (Fraunhofer-Institut für Angewandte Festkörperphysik), Daniela Bleh (Fraunhofer-Institut für Angewandte Festkörperphysik), Joachim Wagner (Fraunhofer-Institut für Angewandte Festkörperphysik), André Merten (Fraunhofer-Institut für Photonische Mikrosysteme), Jan Grahmann (Fraunhofer-Institut für Photonische Mikrosysteme), Harald Schenk (Fraunhofer-Institut für Photonische Mikrosysteme) 5-Feb-14, 2:10 PM In situ process information in the chemical, pharmaceutical or food industry as well as emission monitoring, sensitive trace detection and biological sensing applications would increasingly rely on MIR-spectroscopic analysis in the 3 µm – 12 µm wavelength range, if cost effective, portable, low power consuming and fast spectrometers with a wide tuning range were available. To provide these MIR-spectrometer properties, the combination of quantum cascade lasers with a MOEMS scanning grating as wavelength selective element in the external cavity is addressed to provide a very compact tunable laser source for spectroscopic analysis. 8979-11, Use of high-radiant flux, high-resolution DMD light engines in industrial applications; Alexandra Müller (In Vision) 5-Feb-14, 2:20 PM Illumination systems and imaging systems of industrial projectors in applications like lithography, 3D printing and so on have special demands that differ in many points from commercial home projection systems. We developed a light engine that emphasizes on High uniformity of illumination – for uniform chemical reaction; High radiant flux – for fast chemical reaction; Extreme low image distortion – for accuracy of the printed object; Near telecentricity – for accuracy of the printed object; Short wave length – for good chemical reactivity; Very high resolution – for high detail resolution up to the object corners These measures are strictly necessary for obtaining highest quality of the work piece. 8977-8, Wafer-level vacuum-packaged two-axis MEMS scanning mirror for pico-projector application; Ulrich Hofmann (Fraunhofer-Institut für Siliziumtechnologie), Joachim Janes (Fraunhofer-Institut für Siliziumtechnologie), Frank Senger (Fraunhofer-Institut für Siliziumtechnologie), Christian Mallas (Fraunhofer-Institut für Siliziumtechnologie), Thomas von Wantoch (Fraunhofer-Institut für Siliziumtechnologie) 5-Feb-14, 2:50 PM Hermetic wafer level vacuum packaging of MEMS scanning mirrors effectively protects the MEMS device against contamination and enables to realize high resolution biaxial scanning mirrors for pico-projector display applications. But resonant operation of both axes of a high-Q scanning mirror can also cause disturbing flicker image artifacts depending on the frequency ratio of the two scan axes. This paper reports on modelling fabrication and characterization of an improved MEMS mirror design to avoid such artifacts. 8977-14, High-speed 32×32 MEMS optical-phased array; Connie Chang-Hasnain (Univ of California, Berkeley), Mischa Megens (Univ of California, Davis), Byung-Wook Yoo (Univ. of California, Berkeley), Weijian Yang (Univ. of California, Berkeley), Tianbo Sun (Univ. of California, Berkeley), Ming Wu (Univ. of California, Berkeley), Trevor Chan (Univ. of California, Davis), David Horsley (Univ. of California, Davis) 6-Feb-14, 8:00 AM We report on a novel 32×32 MEMS OPA with fast response time (<4 microseconds), large field of view (±2°), and narrow beam divergence (0.1°). The OPA is composed of high-contrast grating (HCG) mirrors which function as phase shifters and operate at a bandwidth over 500 kHz. Each 20×20 micron-squared


HCG mirror consists of a subwavelength grating patterned into a single 300 nm layer of polysilicon and achieves >99% reflectivity. Beamsteering is demonstrated using both binary and analog phase patterns. A closed-loop phase control system based on a phase-shifting interferometer provides in-situ phase measurement of each mirror in the array. 8977-20, Holographic display with a FPD-based complex spatial light modulator; Gee-Young Sung (Display Device Group, Samsung Advanced Institute of Technology), Young-Jun Yun (Display Device Group, Samsung Advanced Institute of Technology), Jae-eun Jung (Display Device Group, Samsung Advanced Institute of Technology), Jesada Ungnapatanin (Display Device Group, Samsung Advanced Institute of Technology), Hwi Kim (Korea Univ. Sejong Campus), Hong-Seok Lee (Samsung Advanced Institute of Technology), U-In Chung (Samsung Advanced Institute of Technology), Song Hoon (Samsung Advanced Institute of Technology), Jungkwuen An (Samsung Advanced Institute of Technology), Kang-Hee Won (Samsung Advanced Institute of Technology), Da-jung Lim (School of Electrical Engineering, Korea University) 6-Feb-14, 10:40 AM We demonstrate a holographic image reconstructed by a FPD-based complex spatial light modulator (SLM) which comprises a phase SLM and a sheet of beam combiner. Two different phases from the two pixels on the phase-only SLM were combined through the beam combiner in order to modulate amplitude and phase independently for the complex modulation. The holographic image by the proposed complex SLM is verified by the experimental and simulation work in a monochromatic reconstruction. This complex SLM can be scaled up and it is promising candidates for a large-size holographic display. 8977-28, MEMS optical tunable filter based on free-standing sub-wavelength silicon layers; Diaa Khalil (Ain Shams Univ.), Mohamed Shalaby (Ain Shams Univ.), Yasser Sabry (Ain Shams Univ.), Haitham Omran (Ain Shams Univ.), Mohamed Sadek (Si-Ware Systems), Khaled Hassan (Si-Ware Systems) 6-Feb-14, 3:10 PM We report a MEMS optical tunable filter based on high-aspect-ratio etching of sub-wavelength silicon layers on a silicon-on-insulator wafer. The reported filter has measured free-spectral and filter-tuning ranges of approximately 100 nm and a finesse of about 20 around a wavelength of 1550 nm, enabled by the use of 1000 nm-thick silicon layers and a balanced tilt-free motion using a lithographically-aligned electrostatic actuator. The average insertion loss of the filter is about 12 dB with a superior wavelength-dependent loss of about 1.5 dB. The filter has an out-of-band to in-band wavelength rejection ratio that is better than 20 dB. The reported filter experimental characteristics and its integrability are suitable for the production of integrated swept sources for optical coherence tomography application and miniaturized spectrometers.


8993-1, Smart Sensors: why and when the origin was and why and where the future will be; Carlo Corsi (Consorzio CREO) 2-Feb-14, 8:15 AM Smart Sensors, Sensors with interior Intelligence in extracting threat signals from IR clutter/unwanted signals , were developed in the 70’s to supply the limits of signal read-out processing in complex military IR scenarios In the 90’s the integrated signal read-out and processing achieved by integrating VLSI processor technology and mosaic EO detector array technology allowed to develop new generations of Smart Sensors with some basic functions of living eyes(dynamic stare, non-uniformity compensation, spatial and temporal filtering).New and future technologies (Nanotechnology, Bio-Organic Electronics, Bio-Computing ) are lightning a new generation of Smart Sensors extending the Smartness to Spectroscopic Functional Multi-Domain Signal Processing. History and future forecasting of Smart Sensors will be reported. 8983-1, Molecular engineering routes for quadratic nonlinear optics: the role of metal and lanthnide complexes for multifunctional nonlinear materials; Joseph Zyss (Ecole Normale Supérieure de Cachan), Isabelle Ledoux-Rak (Ecole Normale Supérieure de Cachan), Anu Singh (Ecole Normale Supérieure de Cachan) 3-Feb-14, 8:00 AM We present an overview and a few examples of molecular engineering routes for quadratic nonlinear optics (NLO) based on metal complexes and lanthanide derivatives. We will focus of multifunctional complexes (NLO and photochromism, NLO and luminescence) with a fine tuning of these properties by an adequate choice of electro-active substituents of the ligand and of metal or rare earth ions. Three-dimensional intramolecular charge transfer processes are evidenced by NLO measurements, resulting in huge quadratic hyperpolarizability values in lanthanide-phthalocyanine sandwich complexes. In the case of photochromic molecules, we evidence a highly efficient photo-triggered NLO enhancement (50) in octupolar and dipolar complexes. 8993-2, Massively-parallel intracavity trace molecular detection in the mid-infrared using broadband frequency combs; Konstantin Vodopyanov (CREOL, College of Optics and Photonics, Univ. of Central Florida) 3-Feb-14, 8:30 AM We generate ultra-broadband mid-IR frequency combs suitable for coherent Fourier transform spectroscopy using synchronously pumped optical parametric oscillators (OPOs) based on either periodically poled lithium niobate (PPLN) with a femtosecond Er-doped fiber laser as pump, or an orientation-patterned GaAs pumped by a Tm-doped fiber laser. Both OPOs operate near degeneracy to obtain the broadest bandwidth, which reached more than one octave (2.5-6.1 ?m) in the case of Tm-fiber-pumped GaAs OPO. Intracavity spectroscopy of methane, isotopic carbon dioxide (13CO2), carbon monoxide, formaldehyde, ethylene and acetylene was performed by injecting trace amounts of gas directly into the OPO enclosure, or by using an intra-cavity gas cell with a volume ~30 cm³. Ro-vibrational absorption mid-IR spectra were measured in the Fourier domain with massive parallelism of data acquisition. We were able to detect several molecules simultaneously in a mixture and observed significant effective path length enhancement due to the intracavity effect. Detection limits in the ppb-range were demonstrated.


8984-19, Ultrafast spectroscopy of carbon nanomaterials; Junichiro Kono (Rice Univ.) 3-Feb-14, 10:30 AM Carbon-based nanomaterials—single-wall carbon nanotubes (SWCNTs) and graphene, in particular—have emerged in the last decade as novel low-dimensional systems with extraordinary properties. Because they are direct-bandgap systems, SWCNTs are one of the leading candidates to unify electronic and optical functions in nanoscale circuitry; their diameter-dependent bandgaps can be utilized for multi-wavelength devices. Graphene's ultrahigh carrier mobilities are promising for high-frequency electronic devices, while, at the same time, it is predicted to have ideal properties for terahertz generation and detection due to its unique zero-gap, zero-mass band structure. There have been a large number of basic optical studies on these materials, but most of them were performed in the weak-excitation, quasi-equilibrium regime. This talk will give an overview on our recent work on their ultrafast and nonlinear optical properties as well as THz properties. 8981-6, Group IV clathrates: synthesis, optoelectonic properties, and photovoltaic applications; Adele Tamboli (Colorado School of Mines), Aaron Martinez (Colorado School of Mines), Lauryn Baranowski (Colorado School of Mines), Lakshmi Krishna (Colorado School of Mines), Mark Lusk (Colorado School of Mines), Eric Toberer (Colorado School of Mines) 3-Feb-14, 11:00 AM Although Si dominates the photovoltaics market, only two forms of Si are common: amorphous Si and Si in the diamond structure. Silicon can form in other allotropes, including clathrate structures, inclusion compounds consisting of a Si framework surrounding templating guest atoms, which can later be removed. Si-Ge clathrate alloys have a direct band gap that is tunable from 1.9 to 0.6 eV, enabling a variety of applications. We are exploring the potential of this class of materials for optoelectronic and photovoltaic applications using electronic structure calculations, powder synthesis, film synthesis, and optical and structural characterization. 8981-8, Micrometric characterization methods of thin-film solar cells using luminescence emissions; Laurent Lombez (Institut de Recherche et Développement sur l'Energie Photovoltaïque), Jean-François Guillemoles (Institut de Recherche et Développement sur l'Energie Photovoltaïque), Myriam Paire (Institut de Recherche et Développement sur l'Energie Photovoltaïque), Amaury Delamarre (Institut de Recherche et Développement sur l'Energie Photovoltaïque), Gilbert El-Hajje (IRDEP) 3-Feb-14, 11:50 AM Spatial characterization methods of solar cells allow investigating carrier transports as well as spatial fluctuations of the optoelectronic properties. In CIGS cells, variations of minority carrier lifetimes and collection efficiencies are reported, and their influence on the efficiencies needs to be clarified. To this purpose, we record spectrally resolved photoluminescence and electroluminescence images in absolute values, with spatial resolution below 2 µm. From electroluminescence emissions, spatial carrier collection efficiencies are obtained with the reciprocity relations. From photoluminescence, maps of the quasi-Fermi level splitting are determined. Comparison with electroluminescence images allows distinguishing variations of carrier lifetime properties and collection efficiencies.


8981-10, Enhanced performance of up-conversion photovoltaic (UC-PV) devices via photonic crystals and plasmonic layers; Bryce Richards (Heriot-Watt Univ.), Jose Marques-Hueso (Heriot-Watt Univ.), Sean MacDougall (Heriot-Watt Univ.), Jonathan Morton (Heriot-Watt Univ.), Eliyas Mammo (Heriot-Watt Univ.), Georgios Arnaoutakis (Heriot-Watt Univ.), Aruna Ivaturi (Heriot-Watt Univ.), Karl Krämer (Univ. Bern) 3-Feb-14, 2:00 PM Up-conversion photovoltaic (UC-PV) devices offer one route to overcome the Shockley-Queisser limit for single junction solar cells. There have been many papers examining the application of Er3+-doped UC layers for silicon solar cells with photoluminescent quantum yields, external quantum efficiencies and, more recently, short-circuit current densities being reported. The further realization of UC-PV devices is limited by the non-linear nature of the UC process and thus the relatively low efficiencies, or the narrow bandwidths over which Er3+ can weakly absorb and up-convert sunlight? This paper examines ways in which photonic crystals and plasmonics might help UC-PV devices overcome performance short-comings. 8981-15, Hot-carrier solar cell spectral insensitivity: Why develop the hot carrier solar cell when we have multi-junction devices?; Simon Philipps (Fraunhofer-Institut für Solare Energiesysteme), Andreas Bett (Fraunhofer-Institut für Solare Energiesysteme), Raymond Hoheisel (The George Washington Univ.), Matthew Lumb (The George Washington Univ.), Louise Hirst (U. S. Naval Research Laboratory), Robert Walters (U.S. Naval Research Lab.) 3-Feb-14, 4:20 PM Multi-junction and hot carrier devices have comparable limiting efficiency however, multi-junction devices are at a much more advanced stage of development. In this paper we address the question Why develop the hot carrier solar cell when we have multi-junction devices? We calculate material parameters required to produce hot carrier efficiency comparable to multi-junction devices and identify spectral insensitivity of hot carrier solar cells as a key motivation for this development. We show hot carrier solar cells are much less sensitive to seasonal and diurnal spectral changes, enhancing annual energy yields. Performance of these devices is also less location dependent. 8983-19, Laser trapping studies toward fabrication of organic materials and devices; Teruki Sugiyama (Instrument Technology Research Ctr.), Anwar Usman (King Abdullah Univ. of Science and Technology), Ken-ichi Yuyama (National Chiao Tung Univ.), Hiroshi Masuhara (National Chiao Tung Univ.) 4-Feb-14, 10:30 AM Upon focusing intense CW and femtosecond lasers with a few hundreds mW into a diffraction limit, small nano-objects such as molecular clusters, polymers, and particles can be trapped in solution at room temperature, opening new applications for organic photonic materials. Laser trapping induces unique molecular association, localizes photo-polymerization and confines solidification, and enables crystallization and crystal growth control. Laser trapping by femtosecond pulses is more efficient than CW laser trapping and induces novel scattering behavior. As organic photonic materials have high polarizability and regarded as nice target for laser trapping, their fabrication and functional development by laser rapping are promising.


9002-20, Quantum cascade lasers comb spectrometers; Stéphane Blaser (Alpes Lasers SA), Giacomo Scalari (Alpes Lasers SA), Markus Roesch (ETH Zurich), Jérôme Faist (ETH Zurich), Andreas Hugi (ETH Zurich), Gustavo Villares (ETH Zurich), Mattias Beck (ETH Zurich), Hui Chun Liu (Shanghai Jiao Tong Univ.) 4-Feb-14, 10:30 AM The quantum cascade laser has demonstrated the ability to provide gain over a very broad wavelength range. Recently, we have shown that such broadband devices, when operated in continuous wave, emit as a coherent optical comb1 in which the phase relation between the comb modes corresponds approximately to a FM modulated laser. These new comb lasers enables the fabrication of a dual comb spectrometer based on a quantum cascade laser that offers a broadband, all solid-state spectrometer with no moving parts and a ultrafast acquisition time. We discuss also the extension of these ideas to the THz. 1. A. Hugi, G. Villares, S. Blaser, H. C. Liu and J. Faist, Nature 492 (7428), 229-233 (2012). 8994-23, Optical properties of graphene: from the THz to the UV; Tony F. Heinz (Columbia Univ.) 4-Feb-14, 3:50 PM No abstract. 9002-30, Monolithic integration of III-V quantum-dot lasers on silicon substrate; Huiyun Liu (Univ. College London), Mingchu Tang (University College London), Jiang Wu (University College London), Alwyn Seeds (University College London), Qi Jiang (University College London), Andrew Lee (University College London) 4-Feb-14, 4:30 PM Direct epitaxy growth of III-V materials on Si has the potential to fulfil a long desire for efficient light source on Si photonics. The large lattice mismatch between Si and most III-V semiconductors makes the integration of these two challenging. Driven by the urgent demand for efficient light emitters on Si, a few methods have been adopted to optimize the direct epitaxy of III-V materials on Si. High quality III-V epi-layers have been obtained and III-V quantum dot lasers with state-of-the-art performance have been achieved on Si, Ge, and Ge-on-Si substrates. 8983-33, Electroactive vibrantly-colored processable conjugated polymers in display- and window-type devices; John Reynolds (Georgia Institute of Technology) 5-Feb-14, 8:20 AM Electrochromic materials are potentially useful for color-changing displays and dynamic windows with the active materials varying from transition metal oxides, ionic metal complexes, conjugated organic molecules, and conjugated polymers. With their relatively fast switching rates, mechanical flexibility, low redox potentials, and highly transmissive oxidized states, soluble and processable conjugated polymers provide a suite of properties desirable for both application types. Our group has created a set of conjugated polymers with a complete color palette that spans the visible spectrum with neutral state colors that range from yellow, orange, red, magenta, green, cyan, blue, and black. Their high level of solubility allows for processing using a variety of methods including roll-to-roll coating, inkjet printing, and spray-coating. This presentation will outline our efforts in developing this full family of electrochromics polymers. We will overview advanced characterization methods for measuring the electrochemical, spectroscopic, and colorimetric properties of these polymers, including monitoring color properties during dynamic switching, along with rapid spectral recording for definition of switching speeds. Using electrochromic devices (absorptive/transmissive and absorptive/reflective types) as a characterization platform, we demonstrate how these colored-to-transmissive switching polymers behave in regards to color, spectra, switching speed, lifetime, durability, and bistability.


8989-1, III-V semiconductor optoelectronic devices from UV to THz: recent advances and future trends; Manijeh Razeghi (Northwestern Univ.) 5-Feb-14, 8:30 AM Nature offers us different kinds of atoms, but it takes human intelligence to put them together in an elegant way in order to realize functional structures not found in nature. The so-called III-V semiconductors are made of atoms from columns III ( B, Al, Ga, In. Tl) and columns V( N, As, P, Sb, Bi) of the periodic table, and constitute a particularly rich variety of compounds with many useful optical and electronic properties. Guided by highly accurate simulations of the electronic structure, modern semiconductor optoelectronic devices are literally made atom by atom using advanced growth technology such as Molecular Beam Epitaxy (MBE) and Metal Organic Chemical Vapor Deposition (MOCVD). Recent breakthroughs have brought quantum engineering to an unprecedented level, creating light detectors and emitters over an extremely wide spectral range from 0.2 um to 300 um. Nitrogen serves as the best column V element for the short wavelength side of the electromagnetic spectrum, where we have demonstrated III-nitride light emitting diodes and photo detectors in the deep ultraviolet to visible wavelengths. In the infrared, III-V compounds using phosphorus , arsenic and antimony from column V , and indium, gallium, aluminum, , and thallium from column III elements can create interband and intrsuband lasers and detectors based on quantum-dot (QD) or type-II superlattice (T2SL). These are fast becoming the choice of technology in crucial applications such as environmental monitoring and space exploration. Last but not the least, on the far-infrared end of the electromagnetic spectrum, also known as the terahertz (THz) region, III-V semiconductors offer a unique solution of generating THz waves in a compact device at room temperature. Continued effort is being devoted to all of the above mentioned areas with the intention to develop smart technologies that meet the current challenges in environment, health, security, and energy. This talk will highlight my contributions to the world of III-V semiconductor Nano scale optoelectronics, devices from deep-UV to THz. 8981-35, Ag nanoparticle-blended plasmonic organic solar cells: performance enhancement or detraction?; Bo Wu (Nanyang Technological Univ.), Nripan Mathews (Nanyang Technological Univ.), Tze Chien Sum (Nanyang Technological Univ.) 5-Feb-14, 11:10 AM Metallic nanoparticles are commonly used to facilitate light trapping in organic solar cells, but they can also reduce cell performance. Herein, through transient optical spectroscopy complemented with electrical measurements, we uncover evidence that a trap-assisted recombination of charge carriers leads to degradation, irrespective of an initially enhanced absorption and excitation. 9009-9, Characterization of multi-mode fibers and devices for MIMO communications; Nicolas Fontaine (Alcatel-Lucent Bell Labs) 5-Feb-14, 11:15 AM Space-division multiplexing (SDM) systems transmit over multiple spatial-paths to increase capacity or photon efficiency. In these links, coupling between the spatial paths scramble each input signal across all the output channels. This scrambling is described by a $N \times N$ frequency dependent transfer matrix which can be undone using multiple-input multiple-output processing. Using a swept-wavelength interferometer with spatial diversity, we can completely characterize the amplitude and phase transmission between each input and output across the entire C-band in a single 100-ms scan. Matrix eigenanalysis of the transfer matrix enables extraction of the system's insertion loss, mode-dependent loss, and the principle-states of polarization. Results will include transfer matrix measurements of few-mode fibers, coupled-core fibers, photonic lantern spatial-multiplexers, and SDM compatible wavelength routing components.


8993-5, Monolithic QCL design approaches for improved reliability and affordability; Kwok Keung Law (Naval Air Warfare Ctr. Weapons Div.) 6-Feb-14, 8:00 AM Many advances have been made recently in mid-wave infrared and long-wave infrared quantum cascade lasers (QCLs) technologies, and there is an increasing demand for these laser sources for ever expanding Naval, DOD and homeland security applications. We will discuss in this presentation a portfolio of various Naval Air Warfare Weapons Division’s current and future small business innovative research programs and efforts on significantly improving QCLs’ performance, affordability and reliability. 8993-6, Near-infrared OPO in an AlGaAs/AlOx waveguide; Loïc Lanco (Lab. de Photonique et de Nanostructures, CNRS), Xavier Lafosse (Lab. de Photonique et de Nanostructures, CNRS), Giuseppe Leo (Univ. Paris Diderot, Lab. Matériaux et Phénomènes Quantiques, CNRS), Cécile Ozanam (Univ. Paris Diderot, Lab. Matériaux et Phénomènes Quantiques, CNRS), Marc Savanier (Univ. Paris Diderot, Lab. Matériaux et Phénomènes Quantiques, CNRS), Sara Ducci (Univ. Paris Diderot, Lab. Matériaux et Phénomènes Quantiques, CNRS), Ivan Favero (Univ. Paris Diderot, Lab. Matériaux et Phénomènes Quantiques, CNRS), Alessio Andronico (Univ. Paris Diderot, Lab. Matériaux et Phénomènes Quantiques, CNRS) 6-Feb-14, 8:30 AM We demonstrate the first integrated near-infrared OPO in III-V semiconductor, based on a selectively oxidized GaAs/AlOx heterostructure. We observe a CW threshold of 210 mW at degeneracy, in a doubly resonant scheme with dichroic monolithic SiO2/TiO2 Bragg mirrors. This result was obtained via type-I form-birefringent phase matching, with a TM00 pump around 1 µm and TE00 signal and idler around 2 µm, thanks to the high non-resonant ?(2) of GaAs and to relatively weak guided-wave optical losses. Further improvements can be achieved by adopting a double-pump-pass scheme, and optimizing the waveguide optical losses via the amelioration of AlAs oxidation process. 8997-24, Quantum nonlinear optics using cold atomic ensembles; Alexey Gorshkov (California Institute of Technology), Mikhail Lukin (Harvard Univ.), Ofer Firstenberg (Harvard Univ.), Vladan Vuletic (Massachusetts Institute of Technology), Qi-Yu Liang (MIT), Thibault Peyronel (MIT) 6-Feb-14, 11:00 AM Optical nonlinearities at the single photon level are a long-standing goal of optical science, with important technological and scientific implications, such as all-optical switches and photonic quantum computation. By coherently coupling slowly propagating photons to Rydberg states in a cold atomic gas, we create a medium with large optical nonlinearities at the single photon level. We first demonstrate that the Rydberg blockade leads to dissipative photon-photon interactions, preventing the simultaneous propagation of photons in an otherwise transparent medium. We also demonstrate coherent interactions at the single photon level, resulting in large conditional phase-shifts and entanglement. In this dispersive regime, the photons behave as massive particles bound by an attractive force.

Documents

Hot Topics at Photonics West - SPIE