ESO seminar December 2005 Dainis Dravins Lund Observatory

ESO seminar December 2005ESO seminar December 2005

Dainis Dravins

Lund Observatory

What information is contained in light?

What is being observed ? What is not ?

Quantum optics in astronomy?Quantum optics in astronomy?

BLACKBODY ---

SCATTERED ---

SYNCHROTRON ---

LASER ---

CHERENKOV ---

COHERENT ---

WAVELE

NG

TH

& P

OLA

RIZ

ATIO

N F

ILTERS

OBSERVER

http://home.achilles.net/~ypvsj/index.html

BLACKBODY ---

SCATTERED ---

SYNCHROTRON ---

LASER ---

CHERENKOV ---

COHERENT ---

WAVELE

NG

TH

& P

OLA

RIZ

ATIO

N F

ILTERS

OBSERVER

http://home.achilles.net/~ypvsj/index.html

Intensity interferometryIntensity interferometry

Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)


R.Hanbury Brown, J.Davis, L.R.Allen, MNRAS 137, 375 (1967)

Roy Glauber

Nobel prize in physics

Stockholm, December 2005

Information content of light. IInformation content of light. I

D.Dravins, ESO Messenger 78, 9 (1994)

Galileo’s telescopes (1609)

Instruments measuring first-order spatial coherence

Hubble Space Telescope (1990)

HARPS (2003)

Fraunhofer’s spectroscope (1814)

Instruments measuring first-order temporal coherence

Information content of light. IIInformation content of light. II


R. Loudon The

Quantum Theory of

Light (2000)

PHOTON STATISTICS

Semi-classical model of light: (a) Constant classical intensity produces photo-electrons with Poisson statistics; (b) Thermal light results in a compound

Poisson process with a Bose-Einstein distribution, and ‘bunching’ of the photo-electrons (J.C. Dainty)

Information content of light. IIIInformation content of light. III


Quantum effects in cosmic light


Examples ofastrophysical

lasers

Early thoughts about lasers in space

Early thoughts about lasers in space

D. Menzel : Physical Processes in Gaseous Nebulae. I , ApJ 85, 330 (1937)

J. TalbotLaser Action in Recombining PlasmasM.Sc. thesis, University of Ottawa (1995)

Hydrogen recombination lasers & masers in MWC 349A

Circumstellar disk surrounding the hot star.Maser emissions occur in outer regions while lasers operate nearer to the central

star.



Hydrogen recombinationlasers & masersin MWC 349 A

K.H. Hofmann; Y. Balega; N.R. Ikhsanov; A.S. Miroshnichenko; G. WeigeltBispectrum speckle interferometry of the B[e] star MWC 349AA&A 395, 891 (2002)

Two-dimensional visibilityof MWC 349, from speckle

interferometry on theSAO 6m telescope (J-band; λ 1.24 μm,resolution 43 mas).

It appears that the star

is surrounded by acircumstellar disk

seen almost edge-on.

V. Strelnitski; M.R. Haas; H.A. Smith; E.F. Erickson; S.W. Colgan; D.J. HollenbachFar-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A Science 272, 1459 (1996)

V. Strelnitski; M.R. Haas; H.A. Smith; E.F. Erickson; S.W. Colgan; D.J. HollenbachFar-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A Science 272, 1459 (1996)

Quantum Optics & CosmologyQuantum Optics & Cosmology

The First Masersin the Universe…

M. Spaans & C.A. NormanHydrogen Recombination Line Masers at the Epochs of Recombination and ReionizationApJ 488, 27 (1997)

FIRSTMASERSIN THE

UNIVERSE

The black inner regiondenotes the evolutionof the universe before

decoupling.

Arrows indicate maseremission from the epoch

of recombination andreionization.

M. Spaans & C.A. NormanHydrogen Recombination Line Masers at the Epochs of Recombination and ReionizationApJ 488, 27 (1997)

Top to bottom:Three maser spots withnα = 60 produced at z 1000, if regions with density fluctuationsexisted at recombination.

Superposed structure resultsfrom absorption during reionization.Left to right:Profiles for other frequenciesalong the same line of sight.

Brightness temperatures 10 MK are expected.

Synergy OWL ― SKASynergy OWL ― SKA

SKA: Hydrogen recombination

lasers in the very early Universe

OWL: Hydrogen recombination lasers in

the nearby Universe



Emission-line lasersin Eta Carinae

Eta Carinae

HST

Visual magnitude

ESO VLT

Eta Carinae

5.5 year cyclic variation at 6 cm (Stephen White, ANTF )

Model of a compact gas condensation near η Car with its Strömgren boundarybetween photoionized (H II) and neutral (H I) regions

S. Johansson & V. S. LetokhovLaser Action in a Gas Condensation in the Vicinity of a Hot StarJETP Lett. 75, 495 (2002) = Pis’ma Zh.Eksp.Teor.Fiz. 75, 591 (2002)

S. Johansson & V.S. LetokhovAstrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta CarinaeA&A 428, 497 (2004)





Laser effects inWolf-Rayet,

symbiotic stars,& novae

Sketch of the symbiotic star RW Hydrae

P. P. Sorokin & J. H. GlowniaLasers without inversion (LWI) in Space: A possible explanation for intense, narrow-band, emissions that dominate the visible and/or far-UV (FUV) spectra of certain astronomical objectsA&A 384, 350 (2002)

Raman scattered emission bands in the symbiotic star V1016 Cyg

H. M. SchmidIdentification of the emission bands at λλ 6830, 7088A&A 211, L31 (1989)



Emission fromneutron stars,

pulsars & magnetars

T.H. Hankins, J.S. Kern, J.C. Weatherall, J.A. EilekNanosecond radio bursts from strong plasma turbulence in the Crab pulsarNature 422, 141 (2003)

A. Shearer, B. Stappers, P. O'Connor, A. Golden, R. Strom, M. Redfern, O. RyanEnhanced Optical Emission During Crab Giant Radio Pulses Science 301, 493 (2003)

Mean optical “giant” pulse (with error bars) superimposed on the average pulse

V.A. Soglasnov et al.Giant Pulses from PSR B1937+21 with Widths ≤ 15 Nanoseconds and Tb ≥ 5×1039 K, the Highest Brightness Temperature Observed in the Universe, ApJ 616, 439 (2004)

Longitudes of giantpulses comparedto the average

profile.Main pulse (top);

Interpulse (bottom)

Coherent emission from magnetars

Coherent emission from magnetars

o Pulsar magnetospheres emit in radio;higher plasma density shifts magnetar emission to visual & IR (= optical emission in anomalous X-ray pulsars?)

o Photon arrival statistics (high brightness temperature bursts; episodic sparking events?). Timescales down to nanoseconds suggested (Eichler et al. 2002)



CO2 lasers onVenus, Mars & Earth

CO2 lasers on Mars

Spectra of Martian CO2 emission line as a function of frequency difference from line center (in MHz). Blue profile is the total emergent intensity in the absence of laser emission. Red profile

is Gaussian fit to laser emission line. Radiation is from a 1.7 arc second beam (half-power width) centered on Chryse Planitia. The emission peak is visible at resolutions R > 1,000,000.

(Mumma et al., 1981)

CO2 lasers on Earth

Vibrational energy states of CO2 and N2 associated with the natural 10.4 μm CO2 laserG.M. Shved, V. P. Ogibalov

Natural population inversion for the CO2 vibrational states in Earth's atmosphereJ. Atmos. Solar-Terrestrial Phys. 62, 993 (2000)

”Random-laser” emission”Random-laser” emission

D.Wiersma, Nature,406, 132 (2000)

”Random-laser” emission”Random-laser” emission

A “random laser” of mm-sized spheres glows with laser-like light. Monochromatic flashes are initiated by a few “lucky” photons that remain inside the material for a

long time.D.Wiersma, Nature,406, 132 (2000)

Letokhov, V. S.Astrophysical LasersQuant. Electr. 32, 1065 (2002) = Kvant. Elektron. 32, 1065 (2002)

Masers and lasers in the active medium particle density -- medium dimension diagram

Quantum Optics @ TelescopesQuantum Optics @ Telescopes

Detectinglaser effects in

astronomical radiation


Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)

S.Johansson & V.S.LetokhovPossibility of Measuring the Width of Narrow Fe II Astrophysical Laser Lines in the Vicinity ofEta Carinae by means of Brown-Twiss-Townes Heterodyne Correlation Interferometryastro-ph/0501246, New Astron. 10, 361 (2005)

S.Johansson & V.S.LetokhovPossibility of Measuring the Width of Narrow Fe II Astrophysical Laser Lines in the Vicinity of Eta Carinae by means of Brown-Twiss-Townes Heterodyne Correlation Interferometryastro-ph/0501246, New Astron. 10, 361 (2005)

Expected dependence of the correlation signal as function of(a) heterodyne frequency detuning and (b) spacing of telescopes d

D. Dravins 1, C. Barbieri

2

V. Da Deppo 3, D. Faria

1, S. Fornasier 2

R. A. E. Fosbury 4, L. Lindegren

1

G. Naletto 3, R. Nilsson

1, T. Occhipinti 3

F. Tamburini

2, H. Uthas 1, L. Zampieri

5

(1) Lund Observatory(2) Dept. of Astronomy, Univ. of Padova

(3) Dept. of Information Engineering, Univ. of Padova(4) ST-ECF, ESO Garching

(5) Astronomical Observatory of Padova

HIGHEST TIME RESOLUTION, REACHING QUANTUM OPTICS

• Other instruments cover seconds and milliseconds

• QUANTEYE will cover milli-, micro-, and nanoseconds, down to the quantum limit !

Photon statistics of laser emissionPhoton statistics of laser emission

• (a) IfIf the light is non-Gaussian, photon statistics will be closer to stable wave(such as in laboratory lasers)

• (b) IfIf the light has been randomized andis close to Gaussian (thermal), photon correlation spectroscopy will reveal the narrowness of the laser light emission

Spectral resolution = 100,000,000 !

Spectral resolution = 100,000,000 !

o To resolve narrow optical laser emission (Δν 10 MHz) requires spectral resolution λ/Δλ 100,000,000

o Achievable by photon-correlation (“self-beating”) spectroscopy ! Resolved at delay time Δt 100 ns

o Method assumes Gaussian (thermal) photon statistics

Photon correlation spectroscopyPhoton correlation spectroscopy

E.R.Pike, in R.A.Smith, ed. Very High Resolution Spectroscopy, p.51 (1976)

LENGTH & TIME FOR SPECTROMETERS OF DIFFERENT RESOLVING POWER


E.R.Pike, in R.A.Smith, ed. Very High Resolution Spectroscopy, p.51 (1976)

LENGTH,TIME &FREQUENCYFORTWO-MODESPECTRUM


o Analogous to spatial informationfrom intensity interferometry,photon correlation spectroscopydoes not reconstruct the shape of

the source spectrum, but “only” gives linewidth information

SECONDS & MILLISECONDS

• Lunar & planetary-ring occultations• Rotation of cometary nuclei• Pulsations from X-ray pulsars• Cataclysmic variable stars• Pulsating white dwarfs• Optical variability around black holes• Flickering of high-luminosity stars• X-ray binaries• Optical pulsars• Gamma-ray burst afterglows

MILLI-, MICRO- & NANOSECONDS

• Millisecond pulsars ?• Variability near black holes ?• Surface convection on white dwarfs ?• Non-radial oscillations in neutron stars ?• Surface structures on neutron-stars ?• Photon bubbles in accretion flows ?• Free-electron lasers around magnetars ? • Astrophysical laser-line emission ?• Spectral resolutions reaching R = 100

million ?• Quantum statistics of photon arrival

times ?

Binary accretion systems

Artwork by Catrina Liljegren - D. Dravins, ESO Messenger 78, 9 (1994)

John M. Blondin

(North Carolina State University)

Hydrodynamics on supercomputers:

Interacting Binary Stars

Photon Bubble

Oscillations in Accretion

Klein, Arons, Jernigan & Hsu ApJ 457, L85

(1996)

Fluctuations of Pulsar Emission

with Sub-Microsecond Time-

Scales

J. Gil, ApSS 110, 293 (1985)

KUIPER-BELT OCCULTATION

S

Diffraction & shadow of irregular 1-km

Kuiper-belt object in front of a point star.

Horizontal axes in km, vertical axis is

stellar flux.

Grey central spot indicates the

geometrical shadow.

(Roques & Moncuquet, 2000)

p-mode oscillating neutron starp-mode oscillating neutron star

1215Y

Non-radial oscillations in neutron starsMcDermott, Van Horn & Hansen, ApJ 325, 725 (1988)

PREVIOUS LIMITATIONS

* CCD-like detectors: Fastest practical frame rates: 1 - 10 ms

* Photon-counting detectors: Limited photon-count rates: ≳ 100 kHz

PRELIMINARY OPTICAL DESIGN

FEASIBILITY OF CONCEPT

* Slice OWL pupil into 100 segments

* Focus light from each pupil segment by one in an array of 100 lenses

* Detect with an array of 100 APD’s

Light collection with a lens array

Each lens has a square aperture, 10 mm side

The beam section is an annulus, with 100 mm external diameter

Array lens mounting concept

5 x 5 array of 20 μm diameter APD detectors (SensL, Cork)

32x32 Single Photon Silicon Avalanche Diode Array Quantum Architecture Group, L'Ecole Polytechnique Fédérale de Lausanne

•

•

“ULTIMATE” DATA RATES

* 1024 x 1024 imaging elements @ 100 spectral & polarization channels

* Each channel photon-counting @ 10 MHz, 1 ns time resolution

* Data @ 1015 photon time-tags per second = 1 PB/s (Petabyte, 1015 B) = some EB/h (Exabyte = 1018 B)

•

•

“REALISTIC” DATA RATES

* 1024 x 1024 imaging elements one wavelength channel at a time

* Each channel photon-counting @ 10 MHz with 1 ns time resolution

* Data @ 1013 photon time-tags per second = 10 TB/s (Terabyte, 1012 B) ≈ 1 PB/min (Petabyte, 1015 B) ≈ 1 EB/few nights (Exabyte = 1018 B)

ROLE OF LARGE TELESCOPES

• VLT’s & ELT’s permit enormously more sensitive searches for high-speed phenomena in astrophysics

• Statistical functions of arriving photon stream increase with at least the square of the intensity

Advantages of very large telescopes

Advantages of very large telescopes

Telescope diameter

Intensity <I> Second-order correlation <I2>

Fourth-order photon statistics <I4>

3.6 m 1 1 1

8.2 m 5 27 720

4 x 8.2 m 21 430 185,000

50 m 193 37,000 1,385,000,000

100 m 770 595,000 355,000,000,000

•

•

INSTRUMENT DEVELOPMENT

* Lund Observatory: Laboratory setup of digital intensity interferometer

* Photon-counting APD’s, correlator time resolution 1.6 nanoseconds

* Simulated stellar observations with two “telescopes” observing a pinhole “star”

•

Digital Intensity Interferometry

Lund Observatory, December 2005

Photons have many properties…

Photons have many properties…

PHOTONORBITALANGULARMOMENTUM !

Photon Orbital Angular Momentum


At microscopic level, interactions have been observedwith helical beams acting as optical tweezers.

A small transparent particle was confined away fromthe axis in the beam's annular ring of light.

The particle's tangential recoil due to the helical phasefronts caused it to orbit around the beam axis.

At the same time, the beam's spin angular momentumcaused the particle to rotate on its own axis.

M.Padgett, J.Courtial, L.Allen, Phys.Today May 2004, p.25

L.Velasco & A.Boardman, University of Salford, U.K.

An electromagnetic field is expressed as a scalar complex function; where the real and the imaginary parts of the field vanish, there is an optical singularity (also called dislocation for analogy with a crystal). This singularity can be either a screw dislocation or an edge-type.

The screw-type ones are optical vortices with a helicoidal wavefront.

Although polarization enables only two photon-spin states, photons can have many orbital-angular-momentum eigenstates, allowing single photons to encode much more information. Harwit, ApJ 597, 1266 (2003)

Spin


POAM



M.Padgett, J.Courtial, L.Allen, Phys.Today May 2004, p.25

For any given l, the beam has l intertwined helical phase fronts.

For helically phased beams, thephase singularity on the axisdictates zero intensity there.

The cross−sectional intensity pattern of all such beams hasan annular character that persistsno matter how tightly the beamis focused.

Max Book: Malstroem de Luxe (Galleri Engström, Stockholm)



* Individual photons can have different POAM states

* Imaging with POAM-manipulated lightmight reveal exoplanets

* Possible natural POAM sources?Rotating Kerr black holes??

Measuring Orbital Angular MomentumMeasuring Orbital Angular Momentum

Photon orbital angular momentumproduced by a spiral phase plate

Martin Harwit, ApJ 597, 1266 (2003)

Prototype POAM experiment with fork hologram

F.Tamburini, G.Umbriaco, G.Anzolin (Univ. of Padua, 2005)Thanks also to: Anton Zeilinger group,

Inst. of Experimental Physics, Univ. of Vienna

The first three orders: ℓ=0,1,2

l=2

l=1

l=0

F.Tamburini, G.Umbriaco, G.Anzolin (University of Padua, 2005)

F.Tamburini, G.Umbriaco, G.Anzolin , C.Barbieri, A.Bianchini (Padua), astro-ph/0505564

FrogEye, the Quantum Coronagraphic mask. The Photon Orbital Angular Momentum and its applications to Astronomy

Photonic astronomy !Photonic astronomy !

• [Almost] all our knowledge of the Universe arrives through photons

• Both individual photons and photon streams are more complex than has been generally appreciated

Quantum Optics @ ELT’s !Quantum Optics @ ELT’s !

• Quantum optics may open a fundamentally new information channel from the Universe !

• ELT’s will bring non-linear optics into astronomy !

Documents

ESO seminar December 2005 Dainis Dravins Lund Observatory