Ultrashort Pulse (USP) Laser – MatterUltrashort Pulse (USP) Laser-Matter Interactions. 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

1

Integrity Service Excellence

Ultrashort Pulse (USP) Laser – Matter

Interactions

5 MAR 2013

Dr. Riq Parra

Program Officer

AFOSR/RTB

Air Force Research Laboratory

DISTRIBUTION A: Approved for public release; distribution is unlimited

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4. TITLE AND SUBTITLE Ultrashort Pulse (USP) Laser-Matter Interactions

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S) 5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Air Force Office of Scientific Research ,AFOSR/RTB,875 N. Randolph,Arlington,VA,22203

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12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited

13. SUPPLEMENTARY NOTES Presented at the AFOSR Spring Review 2013, 4-8 March, Arlington, VA.

14. ABSTRACT

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Report (SAR)

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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

2

500 700 900

nm

25 nm

300 nm

0.002 nm

BANDWITH

Modelocked femtosecond lasers

Light Emitting Diode

Ti:Sapphire modelocked fs laser

Sunlight

He-Ne cw laser

Wik

iped

ia

Wik

iped

ia


time

time

time

time

Pulses!

3

2013 AFOSR SPRING REVIEW 3001O PORTFOLIO OVERVIEW

• The program aims to understand and control light sources exhibiting extreme bandwidth, peak power and temporal characteristics.

• Portfolio sub-areas: optical frequency combs, high-field science, attosecond physics.


4

Applications of USP Lasers

USP Lasers

Secondary Radiation Sources generation of particle & photons • High power THz generation • Extreme ultraviolet

lithography • Biological soft x-ray

microscopy • Non-destructive evaluation • Medical imaging/therapy

Metrology stabilized, ultra-wide bandwidth • Ultra-stable freq sources • Optical waveform synthesis • High precision spectroscopy • Frequency/time transfer • High-capacity comms • Coherent LIDAR • Optical clocks • Calibration

Material Science ultrashort, high peak power • Surgery • Chemical analysis (LIBS) • Surface property

modification • Non-equilibrium ablation • Micromachining • Ultrafast photochemistry • Attochemistry

Propagation in media self-channeling • Remote sensing • Remote tagging • Directed energy • Electronic warfare • Countermeasures • Advanced sonar

Particle Acceleration ultrahigh electric field gradients • Table-top GeV electron

accelerators • MeV ion sources for

imaging • Isotope production • Hadron tumor therapy • Proton-based fast

ignition


5

Outline

– Microresonator-based optical frequency combs

– High peak power, ultrashort pulse laser processing of materials

– Extreme ultraviolet (EUV) comb spectroscopy

– High harmonic interferometry

– Relativistic optics

DISTRIBUTION A: Approved for public release; distribution is unlimited Photo credits: DOI: 10.1038/nature05524, www.attoworld.de, E. Chowdhury (OSU)

6

Outline







7

Optical frequency combs: Frequency & time domains

Source: Kippenberg et al., Science (2011); Diddams. DISTRIBUTION A: Approved for public release; distribution is unlimited

2∆φ

τr.t = 1/fr

t

E(t) ∆φ

Frequency domain

Time domain

8

Metrological applications of optical frequency combs

Source: Newbury, Nature Photonics (2011) DISTRIBUTION A: Approved for public release; distribution is unlimited AFR~I

9

Sou

rce:

Bra

je, P

hysi

cs 3

, 75

(201

0)

Combs in monolithic microresonators

High-Q mm crystalline resonators

top left doi: 10.1038/nphoton.2012.127 right doi: 10.1103/physreva.84.053833 bottom left doi: 10.1103/physrevlett.101.093902

CaF

2

Fused-quartz

MgF

2

Silica toroids

doi:1

0.10

38/n

atur

e064

01

Silicon nitride microrings

doi: 10.1038/nphoton.2009.259


Parametric

Source: Kippenberg et al., Science (2011)

Conventional

10

Octave spanning bandwidths

Source: Del’Haye, Phys. Rev. Lett. 107, 063901 (2011), Okawachi, Opt. Lett. 36, 3398 (2011) DISTRIBUTION A: Approved for public release; distribution is unlimited

250

1200

20 2300

e o m "0 ';::" -20 Cl,)

3: ~ -40

200

1300 1400 1500

2000 1750

140 160 180

Frequency [THz] 150 125

1600 1700 1800 1900 2000 2100 2200 2300 2400

Wavelength [nm]

Wavelength (nm) 1550 1350 1200 1100 1000

++ 850 GHz 160 THz

200 220 240 260 280 300 Frequency (THz)

AFR~I

11

Why microresonators?

Source: Kippenberg et al., Science (2011) DISTRIBUTION A: Approved for public release; distribution is unlimited

Astronomy Spectroscopy

~ I Il l

1

-s <l -..c ~ 0.1 -~ "'0 c co .0

co c :2 0.01 (.) co '-LL

Waveform generation

~~IC:iJl

Optical clocks Telecommunication A1, A2, ... , AN

• ... • • :e

... : Nonlinear

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... Si02

toroid

• Si02 sphere

• 1 E-3 ~~0.~1~~~~~1--~~~~10--~~~~1~00--~~~1~00-0~ HNLF

Mode spacing (GHz)

AFR~I

12

Comb generation dynamics

DISTRIBUTION A: Approved for public release; distribution is unlimited Graphics adapted from Herr, arXiv:1111.3071v1, 2011

Step 1 gain below threshold

Optical Spectrum

pump wP loss

w

AFR~I

13



Step 2 multiple spacmg

w

AFR~I

14



Step 3 cascading

w

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Step 4a native

spac1ng

w

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Step 4b native

spac1ng

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17



Step 5 sub-combs

• • • • • • • • • • • • •

AFR~I

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Step 6 mergmg

o-s:.+s:. ',, ',J

AFR~I

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(FY12 BRI) Microresonator-based optical frequency combs

• Initiative aimed at exploring the fundamental physics of microresonator comb generation.

• Six efforts exploring:

– Spatio-temporal field mapping and control

– Silicon-carbide microdisks

– Silicon nitride resonators

– Mid-IR microresonators

– Time domain characterization

– Dispersion tailoring via slotted waveguides


20

Temporal and Spectral Comb Generation Dynamics

Optical spectrum

RF spectrum Temporal output

Source: http://arxiv.org/abs/1211.1096v3

PI: Alex Gaeta, Cornell


21



PI: Alex Gaeta, Cornell Optical spectrum



22


Transition to modelocking? Source: http://arxiv.org/abs/1211.1096v3

PI: Alex Gaeta, Cornell Optical spectrum



23

99-GHz repetition rate

160-fs pulses

Ultrashort Pulses at 99 GHz


PI: Alex Gaeta, Cornell


24

Outline







25

Long laser pulse Ultrashort pulses

Long laser pulse damages adjacent structures Ultrashort pulses no collateral damage

Source: C. Momma, A. Tunnermann et al., Opt. Commun. 129, 134 (1996) DISTRIBUTION A: Approved for public release; distribution is unlimited

26

Timescales of electron and lattice processes in laser-excited solids

Time-dependent processes in materials

Source: Sundaram, Nat Mater 1, 217 (2002), Mao, Applied Physics A 79, 1695 (2004).

10 – 100 fs

Multi- photon

Tunneling

Avalanche

Excitation mechanisms


27

High peak power, ultrashort pulse laser processing of materials

• Ultrashort laser pulses open up novel possibilities and mechanisms for laser-solid interactions.

• Demonstrated femtosecond laser processing and surface texturing techniques to engineer surface structures & properties (e.g. darkened & colorized metals, hydrophilic & hydrophobic surfaces).

Colorized metals

PI: Chunlei Guo, U of Rochester

Hydrophilic Hydrophobic


28

(FY13 BRI) High peak power, ultrashort pulse laser processing of materials

• Initiative aimed at developing a fundamental understanding of intense field laser ablation/damage in the femtosecond regime.

• Three multi-PI efforts exploring: – Dynamics of ionization – Fundamental dynamics of laser ablation – Defect states in multi-pulse interaction – Effect of structures on laser damage – First principle-based models, non-

adiabatic quantum MD, classical MD – Vary λ = 400 nm – 4 µm, τ = 5 – 1000 fs – Complex beam shapes (Bessel, Airy,

vortex, SSTF beams) – Novel laser-matter interaction geometries

(confined microexplosions, SSTF excitation, few-cycle pulses)

SSTF focus

Gratings

Classical MD


29

Outline







30

High Harmonic Generation (HHG)

Microscopic single-atom physics of HHG

Macroscopic phase-matched harmonic emission

Source: Popmintchev, Nat Photonics 4, 822 (2010), Popmintchev, Science 336, 1287 (2012) DISTRIBUTION A: Approved for public release; distribution is unlimited

2D electron wavepacket quantum simulation

Source: Luis Plaja, U Salamanca

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Direct Frequency Comb Spectroscopy in the Extreme Ultraviolet

PI: Jun Ye, U of Colorado

Source: Cingoz, Nature 482, 68 (2012)

Towards dual comb EUV spectroscopy

COMB 1

COMB 2

Beat notes!

119 nm 97 nm 82 nm 47 nm 71 nm


Unpublished

32

Outline







33

High Harmonic Interferometry to follow chemical reactions

PI: Paul Corkum, NRC

Source: Worner, Nature 466, 604 (2010).

Br2

Br + Br


34

Conical intersections drive the chemistry of complex molecules

Source: Paul Corkum


DISTRIBUTION A: Approved for public release; distribution is unlimited AFR~I

35

Conical Intersection Dynamics in NO2

Source: Wörner, Science 334, 208 (2011)



100 120 140 160 180

bond angle I deg. ~

AFR~I

36

Electronic dynamics near a conical intersection

Source: Wörner, Science 334, 208 (2011)



A

~ -~

~ ~ r. .!21 0.4 r.

j 0.2

~ 2

11 0

13

17 0 50 100 150 200 250 300 -so

harmonic time delay (fs) order

B 0.4

;;; 0.35 c

-~ 0. 8 v c 0.3 ·c; .g 0

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0 100 200 300 0

0 100 200

time delay (fs) time delay (fs)

D

c

300

/ / Diffraction: weak .......... stron

bond angle asym. stretch

AFR~I

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Outline







38

Progress in peak intensity

• Over the last two decades, a 6 order of magnitude increase in achieved focused intensities in table-top systems.

Source: CUOS website

2x1022

Relativistic ions Nonlinearity of vacuum GeV e acceleration e+e- production Nuclear reactions Relativistic plasmas Hard x-ray generation Tunnel ionization High temperature plasma formation Bright x-ray generation Nonperturbative atomic physics High order nonlinear optics Perturbative atomic physics Nonlinear Optics


39

Petawatt class university lasers

University of Texas, 1.1 PW University of Nebraska, 0.7 PW

University of Michigan, 0.3 PW Ohio State University, 0.5 PW

July 16, 2012 First Light


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Laser-driven x-ray sources

• Understanding laser-generated electron beam characteristics is the key to advancing x-ray sources.

• PIC simulations of high intensity short pulse laser interacting with structured targets yields an enhancement in the number and energy of hot electron.

• Monte Carlo simulations using the electron beam source from PIC show enhancement of x-ray production.


PI: Kramer Akli, OSU

Hot electron generation

Enhanced x-ray production

Picture: Courtesy of Kwei-‐Yu Chu and Lawrence Livermore National Laboratory

41

Laser-driven x-rays generation (0.1 – 10 MeV)

• Scattering from a 300 MeV electron beam can Doppler shift a 1-eV energy laser photon to 1.5 MeV energy.

• Demonstrated > 710 MeV electron beams with no detectable low-energy background.

PI: Donald Umstadter, U of Nebraska

Super Sonic Nozzle

E-Beam

Scattering Laser Pulse

Experimental geometry for generating x-rays via Thomson scattering

> 710 MeV electrons

Energy tunability from 0.1 – 0.8 GeV. Monoenergetic: ΔE/E ~ 10 %

Low angular divergence: 1-5 mrad


42

Laser-driven x-rays generation (0.1 – 10 MeV)

0.5 inch thick steel plate



Divergence (mrad) Counts per pixel, x t o3 - 10 Q c 4 a

"' Beam Parameter Sym Value 2 Energy £1= 0.5 Jl pulse

0 Wavelength ). 800 nm

X Pulse duration r., 90 fs (FWH M)

...... Spotsize = UL 9.4 :!: 0.4 J.llll (RMS) ..., Number of laser

Nlascr 34 Wo oscillations/pulse

s. A vcragc power PL 5.6 TW C:Jft.

e,.,"q Normalized field '!! '/1~ OQ 0.4 e,. b s trength

e/1/q Photon energy Et. I.SeV

Interaction angle <1> 170 deg

Source size Ua 6.0 :!: 2.6 J.lln (RMS)

Cutoft' energy; £, 250 MeV X 1019 e

Divergence;; o. 5 mrad (FWHM)

S' 2.5 Total charge Q 120pC v:i .._, Source size a, 5.1 :1: 2.6 J.lm (RMS)

"' "' Divergence o, 12.7 mrad (FWHM) Q) c

1::: Peak energy £, 1.2 MeV ell

·;::: Total photon co y N, -10' "' number/pulse ·:;;: ~ Peak on-axis

2.3 x I 0 19 photonsls-

§ Bx mm2-nu·dd2 (0. 1%

7d brilliance Q)

BW) p...

0·8.o 0.8 1.6 2.4 3.2 4.0 Photon Energy (Me Y)

AFR~I

43

Brighter, more energetic and tunable than conventional synchrotrons

UNL 2012

Hartemann, F. V. et al. High-energy scaling of Compton scattering light sources. Physical Review Special Topics - Accelerators and Beams 8, 100702 (2005).



44

(FY14 BRI) Laser-matter interactions in the relativistic optics regime

• Laser-driven electron acceleration – Laser Wakefield Acceleration: Electrons

are accelerated to gigaelectronvolt (GeV) energies over centimeters distances

– Direct Light Acceleration

• Ion acceleration – Protons and ions are accelerated to

megaelectronvolt (MeV) energies by a mechanism known as ‘target normal sheath acceleration’ (TNSA)

• X-ray radiation sources – keV to MeV x-rays via non‐linear Thomson

Scattering – Kα monochromatic emission – Bremsstrahlung broadband radiation

• Neutron sources

– Protons incident on a secondary target (e.g. Lithium) can produce MeV neutrons

• QED physics DISTRIBUTION A: Approved for public release; distribution is unlimited

Electron density distribution and generation of quasi-monoenergetic electron bunches observed in PIC simulations.

Target Sheath Normal Acceleration: Laser acceleration of protons from the back side of a microstructured target.

45

Summary and outlook

Optical frequency combs ultra-wide bandwidths • Spectral coverage to exceed an

octave with high power/comb. • Coherence across EUV-LWIR. • Novel resonator designs (e.g.

micro-resonator based). • Ultra-broadband pulse shaping. • …

Attosecond science ultrashort pulsewidths • Efficient, high-flux generation. • Pump-probe methods. • Probe atoms/molecules &

condensed matter systems. • Attosecond pulse propagation. • Novel attosecond experiments. • Fundamental interpretations of

attosecond measurements. • …

The program aims to understand and control light sources exhibiting extreme temporal, bandwidth and peak power characteristics.

High-field laser physics high peak powers • Laser-solid interactions. • Fs propagation in media. • Sources of secondary photons. • Compact particle accelerators. • High peak power laser

architectures. • High repetition rates. • New wavelengths of operation. • …


Documents

Ultrashort Pulse (USP) Laser – MatterUltrashort Pulse (USP) Laser-Matter Interactions. 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER