A temperature-stable optical link for the transmission of fast analogue signals

Rose, H. J.; Bradbury, S. M.

doi:10.1016/j.nima.2008.06.039

Cited by 3 publications

(1 citation statement)

References 16 publications

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“…Further additional functionality includes the ability to inject test pulses into the laser-driver to test the link in daylight. The OPA695 amplifier used by R.J. White et al 31 has been superseded by Analog Devices' AD8000, one of a new generation of amplifiers not previously available, which has a comparable slew rate but a quoted input voltage noise of just 1.6 nV / √ Hz. Initial laboratory tests show that a photomultiplier pulse rise time of the order of 2ns can be well reproduced.…”

Section: Front End Electronicsmentioning

confidence: 99%

Stellar intensity interferometry: experimental steps toward long-baseline observations

LeBohec

Adams²,

Bond³

et al. 2010

SPIE Proceedings

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Experiments are in progress to prepare for intensity interferometry with arrays of air Cherenkov telescopes. At the Bonneville Seabase site, near Salt Lake City, a testbed observatory has been set up with two 3-m air Cherenkov telescopes on a 23-m baseline. Cameras are being constructed, with control electronics for either off-or online analysis of the data. At the Lund Observatory (Sweden), in Technion (Israel) and at the University of Utah (USA), laboratory intensity interferometers simulating stellar observations have been set up and experiments are in progress, using various analog and digital correlators, reaching 1.4 ns time resolution, to analyze signals from pairs of laboratory telescopes.

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Section: Front End Electronicsmentioning

confidence: 99%

Stellar intensity interferometry: experimental steps toward long-baseline observations

LeBohec

Adams²,

Bond³

et al. 2010

SPIE Proceedings

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Optical intensity interferometry with the Cherenkov Telescope Array

Dravins

LeBohec

Jensen

et al. 2013

Astroparticle Physics

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With its unprecedented light-collecting area for night-sky observations, the Cherenkov Telescope Array (CTA) holds great potential for also optical stellar astronomy, in particular as a multi-element intensity interferometer for realizing imaging with sub-milliarcsecond angular resolution. Such an order-of-magnitude increase of the spatial resolution achieved in optical astronomy will reveal the surfaces of rotationally flattened stars with structures in their circumstellar disks and winds, or the gas flows between close binaries. Image reconstruction is feasible from the second-order coherence of light, measured as the temporal correlations of arrival times between photons recorded in different telescopes. This technique (once pioneered by Hanbury Brown and Twiss) connects telescopes only with electronic signals and is practically insensitive to atmospheric turbulence and to imperfections in telescope optics. Detector and telescope requirements are very similar to those for imaging air Cherenkov observatories, the main difference being the signal processing (calculating cross correlations between single camera pixels in pairs of telescopes). Observations of brighter stars are not limited by sky brightness, permitting efficient CTA use during also bright-Moon periods. While other concepts have been proposed to realize kilometer-scale optical interferometers of conventional amplitude (phase-) type, both in space and on the ground, their complexity places them much further into the future than CTA, which thus could become the first kilometer-scale optical imager in astronomy. (C) 2012 Elsevier B.V. All rights reserved

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Stellar intensity interferometry: Prospects for sub-milliarcsecond optical imaging

Dravins¹,

LeBohec²,

Jensen³

et al. 2012

New Astronomy Reviews

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a b s t r a c tUsing kilometric arrays of air Cherenkov telescopes at short wavelengths, intensity interferometry may increase the spatial resolution achieved in optical astronomy by an order of magnitude, enabling images of rapidly rotating hot stars with structures in their circumstellar disks and winds, or mapping out patterns of nonradial pulsations across stellar surfaces. Intensity interferometry (once pioneered by Hanbury Brown and Twiss) connects telescopes only electronically, and is practically insensitive to atmospheric turbulence and optical imperfections, permitting observations over long baselines and through large airmasses, also at short optical wavelengths. The required large telescopes ($10 m) with very fast detectors ($ns) are becoming available as the arrays primarily erected to measure Cherenkov light emitted in air by particle cascades initiated by energetic gamma rays. Planned facilities (e.g., CTA, Cherenkov Telescope Array) envision many tens of telescopes distributed over a few square km. Digital signal handling enables very many baselines (from tens of meters to over a kilometer) to be simultaneously synthesized between many pairs of telescopes, while stars may be tracked across the sky with electronic time delays, in effect synthesizing an optical interferometer in software. Simulated observations indicate limiting magnitudes around m V = 8, reaching angular resolutions $30 larcsec in the violet. The signal-to-noise ratio favors high-temperature sources and emission-line structures, and is independent of the optical passband, be it a single spectral line or the broad spectral continuum. Intensity interferometry directly provides the modulus (but not phase) of any spatial frequency component of the source image; for this reason a full image reconstruction requires phase retrieval techniques. This is feasible if sufficient coverage of the interferometric (u, v)-plane is available, as was verified through numerical simulations. Laboratory and field experiments are in progress; test telescopes have been erected, intensity interferometry has been achieved in the laboratory, and first full-scale tests of connecting large Cherenkov telescopes have been carried out. This paper reviews this interferometric method in view of the new possibilities offered by arrays of air Cherenkov telescopes, and outlines observational programs that should become realistic already in the rather near future.

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A temperature-stable optical link for the transmission of fast analogue signals

Cited by 3 publications

References 16 publications

Stellar intensity interferometry: experimental steps toward long-baseline observations

Stellar intensity interferometry: experimental steps toward long-baseline observations

Optical intensity interferometry with the Cherenkov Telescope Array

Stellar intensity interferometry: Prospects for sub-milliarcsecond optical imaging

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