Speckle imaging with the PAPA detector

Papaliolios, C.; Nisenson, P.; Ebstein, Steven M.

doi:10.1364/ao.24.000287

Cited by 58 publications

(22 citation statements)

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“…As an example, we can consider the PAPA camera 12 : at photon rates in excess of -250,000/s the levels of artifacts introduced because of the limited response time of the event-registering electronics' 3 rapidly become unacceptable. Typical limiting fluxes for other photon-counting cameras are even lower than this value (as shown, for example, by the experiments reported later in this paper).…”

Section: Optical Speckle-imaging Regimementioning

confidence: 99%

Diffraction-limited imaging with partially redundant masks I Infrared imaging of bright objects

Haniff

Buscher

1992

J. Opt. Soc. Am. A

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In a recent paper [J. Opt. Soc. Am. A 9, 203 (1992)] the benefits of pupil apodization were examined for the near-infrared imaging of bright sources. In the current paper we extend these considerations to optical speckle imaging, in which photon noise rather than detector readout noise is important. We demonstrate that a one-dimensional pupil geometry (i.e., a thin slit) has several advantages over an unapodized aperture when faint sources are being observed through atmospheric turbulence. The use of a slit aperture does not decrease the signal-to-noise ratios of the power-spectrum and bispectrum measurements, and in many cases it increases them, despite the large reduction in signal level. The disadvantage of this apodization is a reduction in Fourier-plane coverage, which must be compensated for by observations with the slit aligned at several position angles. The performance of many of the current generation of photon-counting imaging detectors deteriorates at the high counting rates that can be experienced even when one is observing sources that are approaching the limiting magnitude of the speckle imaging technique. Under such conditions, we recommend the use of an apodized pupil, in contrast to the current preference for employing a neutral-density filter to reduce the detector count rate.

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Section: Optical Speckle-imaging Regimementioning

confidence: 99%

Diffraction-limited imaging with partially redundant masks I Infrared imaging of bright objects

Haniff

Buscher

1992

J. Opt. Soc. Am. A

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“…PAPA Detectors. PAPA detectors were developed by Papaliolios and Mertz [54] and their collaborators, and first speckle imaging results were first reported in 1985 by Papaliolios et al [55]. The operational principle is shown in Figure 6a.…”

Section: B Photon-counting Devicesmentioning

confidence: 99%

Speckle imaging in astronomy

Horch

1995

Int J Imaging Syst Tech

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This article discusses current research in speckle interferometry and speckle imaging in astronomy. These techniques continue to have a significant impact on problems such as stellar formation, stellar masses, and planetary astronomy. In a regime of increasingly sophisticated and impressive instrumentation designed for high-resolution imaging, there is still an important role for the single-aperture passive technique of speckle imaging. 0 1995 John Wiley & Sons, Inc.

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“…The camera is a 256 χ 256 pixel photon counting array detector operating with speeds upwards of 1 million photons per second and a dead time of 300ns for individual photon events. Its principle of operation has been described by Papaliolios et al (1985). It uses 17 small lenses in an array that provides easy access for optical adjustments, and was optically aligned by the rotation of lenses alone, as described by Lawson (1992).…”

Section: The Sydney University Papa Cameramentioning

confidence: 99%

The Fringe Tracking Servo in SUSI

Lawson

Booth

1994

Symp. - Int. Astron. Union

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Abstract. We present a description of the pathlength compensation system used in the Sydney University Stellar Interferometer, and report on the method of fringe tracking that is being implemented. The components of this system are discussed, including the PAPA camera used to detect chromatic fringes, the fringe tracking servo, the delay line and its control. The Sydney University PAPA cameraA PAPA camera is used in the Sydney University Stellar Interferometer (SUSI) for the observation of group delay fringes in stellar spectra. The camera is a 256 χ 256 pixel photon counting array detector operating with speeds upwards of 1 million photons per second and a dead time of 300ns for individual photon events. Its principle of operation has been described by Papaliolios et al. (1985). It uses 17 small lenses in an array that provides easy access for optical adjustments, and was optically aligned by the rotation of lenses alone, as described by Lawson (1992). Laboratory experiments in group delay trackingIf wavefront tilt is removed from both arms of the interferometer a channeled spectrum can be seen when the light is combined and dispersed. The number of fringes across a fixed bandwidth of a star's spectrum is directly proportional to the pathlength difference between the arriving wavefronts. Short exposure images of stellar spectra can be Fourier transformed and real-time processing used to extract the path difference. Computer simulations and theoretical predictions for this form of tracking have been reported previously by Goodman (1984), Nisenson and Traub (1988), Shao et al. (1988), Buscher (1989), and others.Here we report preliminary results of laboratory tests of this technique. Figure 1 shows the tracking response of the PAPA camera and processor. A Michelson interferometer was used with a sinusoidal pathlength change of 13μπι peak-to-peak at 2.5 Hz introduced into one arm. Light from a Xenon lamp was used as an artificial star and passed through the interferometer, dispersed, and detected. Approximately 100 photons/frame, over a detected bandwidth of lOOnm, were transformed for the power spectra. The resolution in delay is roughly 2μπι. Open-loop performance of the pathlength compensatorThe design of the Optical PathLength Compensator (OPLC) has been outlined previously by Booth et al. (1991) andGilliand (1992). Presently the OPLC uses a single movable carriage which is microstepped under servo control. The carriage is mounted on rails on a 70 m long reinforced concrete pier and is monitored by two independent infrared laser metrology systems. HeCd lasers are used with an operating wavelength of 1.15μπι, and movement errors to an accuracy of 64nm optical path difference (OPD) can be tracked.

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Speckle imaging with the PAPA detector

Cited by 58 publications

References 4 publications

Diffraction-limited imaging with partially redundant masks I Infrared imaging of bright objects

Diffraction-limited imaging with partially redundant masks I Infrared imaging of bright objects

Speckle imaging in astronomy

The Fringe Tracking Servo in SUSI

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