1 / 63

HTRA Galway - June 2006

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 ?. BLACKBODY - --. SCATTERED ---. WAVELENGTH & POLARIZATION FILTERS. LASER ---. COHERENT ---. OBSERVER.

ace
Download Presentation

HTRA Galway - June 2006

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HTRA Galway - June 2006 Dainis Dravins Lund Observatory

  2. Quantum optics in astronomy? What information is contained in light? What is being observed ? What is not ?

  3. BLACKBODY --- SCATTERED --- WAVELENGTH & POLARIZATION FILTERS LASER --- COHERENT --- OBSERVER SYNCHROTRON --- CHERENKOV ---

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

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

  6. Roy Glauber Nobel prize in physics Stockholm, December 2005

  7. Roy Glauber inLund, December 2005

  8. Information content of light. I D.Dravins, ESO Messenger No. 78, 9

  9. Instruments measuring first-order spatial coherence Galileo’s telescopes (1609) Hubble Space Telescope (1990)

  10. Fraunhofer’s spectroscope (1814) Instruments measuring first-order temporal coherence HARPS (2003)

  11. “COMPLEX” RADIATION SOURCES What can a [radio] telescope detect? What can it not?

  12. Information content of light. II D.Dravins, ESO Messenger No. 78, 9

  13. PHOTON STATISTICS R. Loudon The Quantum Theory of Light (2000)

  14. 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)

  15. Information content of light. III D.Dravins, ESO Messenger No. 78, 9

  16. Quantum effects in cosmic light Examples of astrophysical lasers

  17. Early thoughts about lasers in space D. Menzel : Physical Processes in Gaseous Nebulae. I , ApJ 85, 330 (1937)

  18. J. Talbot Laser Action in Recombining Plasmas M.Sc. thesis, University of Ottawa (1995)

  19. Quantum effects in cosmic light Hydrogen recombination lasers & masers in MWC 349 A

  20. 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.

  21. 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)

  22. Quantum Optics & Cosmology The First Masers in the Universe…

  23. 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)

  24. Quantum effects in cosmic light Emission-line lasers in Eta Carinae

  25. HST Eta Carinae ESO VLT Visual magnitude

  26. 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)

  27. S. Johansson & V.S. Letokhov Astrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta Carinae A&A 428, 497 (2004)

  28. S. Johansson & V.S. Letokhov Astrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta Carinae A&A 428, 497 (2004)

  29. S. Johansson & V.S. Letokhov Astrophysical lasers operating in optical Fe II lines in stellar ejecta of Eta Carinae A&A 428, 497 (2004)

  30. Quantum effects in cosmic light Laser effects in Wolf-Rayet, symbiotic stars, & novae

  31. 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)

  32. 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)

  33. Quantum effects in cosmic light Emission from neutron stars, pulsars & magnetars

  34. 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)

  35. 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)

  36. 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)

  37. Coherent emission from magnetars • Pulsar magnetospheres emit in radio; higher plasma density shifts magnetar emission to visual & IR (= optical emission in anomalous X-ray pulsars?) • Photon arrival statistics (high brightness temperature bursts; episodic sparking events?). Timescales down to nanoseconds suggested (Eichler et al. 2002)

  38. Quantum effects in cosmic light CO2 lasers on Venus, Mars & Earth

  39. 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)

  40. 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)

  41. ”Random-laser” emission D.Wiersma, Nature,406, 132 (2000)

  42. 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)

  43. Quantum Optics @ Telescopes Detecting laser effects in astronomical radiation

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

  45. 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)

  46. Spectral resolution = 100,000,000! • To resolve narrow optical laser emission (Δν  10 MHz) requires spectral resolution λ/Δλ  100,000,000 • Achievable by photon-correlation (“self-beating”) spectroscopy! Resolved at delay time Δt 100 ns • Method assumes Gaussian (thermal) photon statistics

  47. 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

  48. 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)

  49. Photon correlation spectroscopy • Analogous to spatial information from intensity interferometry, photon correlation spectroscopy does not reconstruct the shape of the source spectrum, but “only” gives linewidth information

More Related