Avalanche photo diodes in the observatory environment: lucky imaging at 1-2.5 microns

Abstract

The recent availability of large format near-infrared detectors with sub-election readout noise is revolutionizing our approach to wavefront sensing for adaptive optics. However, as with all near-infrared detector technologies, challenges exist in moving from the comfort of the laboratory test-bench into the harsh reality of the observatory environment. As part of the broader adaptive optics program for the GMT, we are developing a near-infrared Lucky Imaging camera for operational deployment at the ANU 2.3 m telescope at Siding Spring Observatory. The system provides an ideal test-bed for the rapidly evolving Selex/SAPHIRA eAPD technology while providing scientific imaging at angular resolution rivalling the Hubble Space Telescope at wavelengths λ = 1.3-2.5 μm.

GMTIFS: The Giant Magellan Telescope integral fields spectrograph and imager

“…Simulations indicate that a sky-coverage of > 80% is straightforward, with Strehl > 0.3, with a number of options for achieving higher sky-coverage currently under consideration. These include the use of the emerging electron Avalanche Photodiode (eAPD) [14,15,16] detectors, and image sharpening of the off-axis guide star via a cooled DM [17] in the OIWFS in an operating mode akin to MOAO operations.…”

“…The preliminary design for the LTAO OIWFS required two Teledyne-H2RG detectors, operating in highly tuned readout modes. The evolving strategy for GMTO AO implementation in all modes, and the availability of extremely low readout noise eAPD detectors [16] means that it is now appropriate for a significant review of the OIFWs concept. This work will be undertaken in 2016/2017 as part of the GMTIFS PDS.…”

“…However, this venerable system is aging and in its current form cannot delver the full-frame rates necessary for large format near-infrared detectors (needed for extensive Fowler sampling for high cadence wavefront sensing). To address the longstanding issues of pick-up noise in the signal lines between cryogenic detector and external control hardware for signal digitization, we have developed a cryogenic preamplification stage [16] currently operating in tandem with an SDSU controller, while we explore a number of promising options for a new technology controller.…”

“…However, the now routine availability of high performance electron Avalanche Photo-Diode (eAPD) detectors such as the SAPHIRA [14,15,16] array from SELEX, that are essential free of readout noise, changes the paradigm for the OIWFS. The baseline will evaluate this emerging technology based a results from our technology demonstrator program that will deploy a SAPHIRA array as Lucky Imager [16] at the ANU 2.3, telescope in early 2017. [5] rs of operation ficantly extend he capabilities gation through ew boundaries n of Professor…”