Transcript QuantEYE - Lund Observatory

HTRA Galway - June 2006
Dainis Dravins
Lund Observatory
Quantum optics in astronomy?
What information is
contained in light?
What is being observed ?
What is not ?
LASER ---
COHERENT ---
CHERENKOV ---
OBSERVER
Intensity interferometry
Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)
Intensity interferometry
R.Hanbury Brown, J.Davis, L.R.Allen, MNRAS 137, 375 (1967)
Roy Glauber
Nobel prize in physics
Stockholm, December 2005
Roy Glauber in Lund, December 2005
Information content of light. I
D.Dravins, ESO Messenger No. 78, 9
Instruments measuring first-order spatial coherence
Galileo’s telescopes (1609)
Hubble Space Telescope (1990)
Fraunhofer’s
spectroscope (1814)
Instruments
measuring
first-order
temporal
coherence
HARPS (2003)
“COMPLEX” RADIATION SOURCES
What can a [radio]
telescope detect?
What can it not?
Information content of light. II
D.Dravins, ESO Messenger No. 78, 9
PHOTON STATISTICS
R. Loudon
The
Quantum
Theory of
Light (2000)
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. III
D.Dravins, ESO Messenger No. 78, 9
Quantum effects in cosmic light
Examples of
astrophysical
lasers
Early thoughts about lasers in space
D. Menzel : Physical Processes in Gaseous Nebulae. I , ApJ 85, 330 (1937)
J. Talbot
Laser Action in Recombining Plasmas
M.Sc. thesis, University of Ottawa (1995)
Quantum effects in cosmic light
Hydrogen recombination
lasers & masers
in MWC 349 A
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.
V. Strelnitski; M.R. Haas; H.A. Smith; E.F. Erickson; S.W. Colgan; D.J. Hollenbach
Far-Infrared Hydrogen Lasers in the Peculiar Star MWC 349A
Science 272, 1459 (1996)
Quantum Optics & Cosmology
The First Masers
in the Universe…
FIRST
MASERS
IN THE
UNIVERSE
The black inner region
denotes the evolution
of the universe before
decoupling.
Arrows indicate maser
emission from the epoch
of recombination and
reionization.
M. Spaans & C.A. Norman
Hydrogen Recombination Line Masers at the Epochs of Recombination and Reionization
ApJ 488, 27 (1997)
Quantum effects in cosmic light
Emission-line lasers
in Eta Carinae
HST
Eta Carinae
ESO VLT
Visual magnitude
Model of a compact gas condensation near η Car with its Strömgren boundary
between photoionized (H II) and neutral (H I) regions
S. Johansson & V. S. Letokhov
Laser Action in a Gas Condensation in the Vicinity of a Hot Star
JETP Lett. 75, 495 (2002) = Pis’ma Zh.Eksp.Teor.Fiz. 75, 591 (2002)
S. Johansson & V.S. Letokhov
Astrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta Carinae
A&A 428, 497 (2004)
S. Johansson & V.S. Letokhov
Astrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta Carinae
A&A 428, 497 (2004)
S. Johansson & V.S. Letokhov
Astrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta Carinae
A&A 428, 497 (2004)
Quantum effects in cosmic light
Laser effects in
Wolf-Rayet,
symbiotic stars,
& novae
Sketch of the symbiotic star RW Hydrae
P. P. Sorokin & J. H. Glownia
Lasers 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 objects
A&A 384, 350 (2002)
Raman scattered emission bands in the symbiotic star V1016 Cyg
H. M. Schmid
Identification of the emission bands at λλ 6830, 7088
A&A 211, L31 (1989)
Quantum effects in cosmic light
Emission from
neutron stars,
pulsars & magnetars
T.H. Hankins, J.S. Kern, J.C. Weatherall, J.A. Eilek
Nanosecond radio bursts from strong plasma turbulence in the Crab pulsar
Nature 422, 141 (2003)
Longitudes of giant
pulses compared
to the average
profile.
Main pulse (top);
Interpulse (bottom)
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)
Mean optical “giant” pulse (with error bars) superimposed on the average pulse
A. Shearer, B. Stappers, P. O'Connor, A. Golden, R. Strom, M. Redfern, O. Ryan
Enhanced Optical Emission During Crab Giant Radio Pulses
Science 301, 493 (2003)
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)
Quantum effects in cosmic light
CO2 lasers on
Venus, 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 laser
G.M. Shved, V. P. Ogibalov
Natural population inversion for the CO2 vibrational states in Earth's atmosphere
J. Atmos. Solar-Terrestrial Phys. 62, 993 (2000)
”Random-laser” emission
D.Wiersma, Nature,406, 132 (2000)
Masers and lasers in the active medium particle-density vs. dimension diagram
Letokhov, V. S.
Astrophysical Lasers
Quant. Electr. 32, 1065 (2002) = Kvant. Elektron. 32, 1065 (2002)
Quantum Optics @ Telescopes
Detecting
laser effects in
astronomical radiation
Intensity interferometry
Narrabri stellar intensity interferomer circa 1970 (R.Hanbury Brown, R.Q.Twiss et al., University of Sydney)
S.Johansson & V.S.Letokhov
Possibility 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 Interferometry
astro-ph/0501246, New Astron. 10, 361 (2005)
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 statistics of laser emission
• (a) If the light is non-Gaussian, photon
statistics will be closer to stable wave
(such as in laboratory lasers)
• (b) If the light has been randomized and
is close to Gaussian (thermal), photon
correlation spectroscopy will reveal the
narrowness of the laser light emission
Photon correlation spectroscopy
LENGTH,
TIME &
FREQUENCY
FOR
TWO-MODE
SPECTRUM
E.R.Pike, in R.A.Smith, ed. Very High Resolution Spectroscopy, p.51 (1976)
Photon correlation spectroscopy
o Analogous to spatial information
from intensity interferometry,
photon correlation spectroscopy
does not reconstruct the shape of
the source spectrum, but “only”
gives linewidth information
D. Dravins 1, C. Barbieri 2
V. DaDeppo 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 !
MILLI-, MICRO- & NANOSECONDS
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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 ?
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 SubMicrosecond
Time-Scales
J. Gil, ApSS 110,
293 (1985)
Rapid oscillations in neutron stars
Detection with RHESSI of High-Frequency X-Ray Oscillations in the Tail of the 2004
Hyperflare from SGR 1806-20: Watts & Strohmayer, ApJ 637, L117 (2006)
Power spectra after main
flare (25–100 keV), at
different rotational phases:
QPO visible at 92.5 Hz.
Possible identification:
Toroidal vibration mode
of neutron-star crust?
Rapid oscillations in neutron stars
Detection with RHESSI of High-Frequency X-Ray Oscillations in the Tail of the 2004
Hyperflare from SGR 1806-20: Watts & Strohmayer, ApJ 637, L117 (2006)
Surface patterns for torsional modes that may have been excited by the hyperflare.
Colors and arrows indicate the magnitude of the vibrations.
(Max Planck Institute for Astrophysics)
p-mode oscillating neutron star
12
15
Y
Non-radial oscillations in neutron stars
McDermott, Van Horn & Hansen, ApJ 325, 725 (1988)
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
21
430
185,000
50 m
193
37,000
1,385,000,000
100 m
770
595,000
355,000,000,000
4 x 8.2 m
. . .