Photonic Astronomy and Quantum Optics

Dainis Dravins, C. Barbieri, R. A. E. Fosbury +6 more

Modern optics focuses on photonics and quantum optics, studying individual photons and statistics of photon streams. Those can be complex and carry information beyond that recorded by imaging, spectroscopy, polarimetry or interferometry. Since [almost] all astronomy is based upon the interpretation of subtleties in the light from astronomical sources, quantum optics has the potential of becoming another information channel from the Universe. The observability of quantum statistics increases rapidly with telescope size making photonic astronomy very timely in an era of very large telescopes.

S. Chua

Dainis Dravins, See Profile, Dainis Dravins

Abstract Quantum optics potentially offers an information channel from the Uni-verse beyond the established ones of imaging and spectroscopy. All existing cam-eras and all spectrometers measure aspects of the first-order spatial and/or temporal coherence of light. However, light has additional degrees of freedom, manifest in the statistics of photon arrival times, or in the amount of photon orbital angular mo-mentum. Such quantum-optical measures may carry information on how the light was created at the source, and whether it reached the observer directly or via some intermediate process. Astronomical quantum optics may help to clarify emission processes in natural laser sources and in the environments of compact objects, while high-speed photon-counting with digital signal handling enables multi-element and long-baseline versions of the intensity interferometer. Time resolutions of nanosec-onds are required, as are large photon fluxes, making photonic astronomy very timely in an era of large telescopes. 1 What Is Observed in Astronomy? Almost all of astronomy depends on the interpretation of properties of electromag-netic radiation (“light”) from celestial sources. The sole exceptions are neutrino detections; gravitational-wave searches; analyses of cosmic rays, meteorites, and other extraterrestrial materials; and in-situ studies of solar-system bodies. All our other understanding of the Universe rests upon observing and interpreting more or less subtle properties in the light reaching us from celestial bodies. Astronomical telescopes are equipped with myriads of auxiliary instruments which, on first sight, may give an impression of being vastly different. However, a closer examination of the underlying physical principles reveals that they all are measuring either the spatial or temporal [first-order] coherence of light (or perhaps some combination of these). All imaging devices (cameras, interferometers) are studying aspects of the spatial coherence (in various directions, and for different angular extents on the sky). All spectrally analyzing devices measure aspects of the

Christophe Couteau

Gal Gumpel, Erez N. Ribak

We describe a new method to overcome the diffraction limit in astronomy, by amplification of photon wave packets. This method was demonstrated in theory, by computer simulation, and is now being experimentally tested.

Thomas P. Pearsall