Near-infrared InGaAs detectors for background-limited imaging and photometry

Abstract

Originally designed for night-vision equipment, InGaAs detectors are beginning to achieve background-limited performance in broadband imaging from the ground. The lower cost of these detectors can enable multi-band instruments, arrays of small telescopes, and large focal planes that would be uneconomical with high-performance HgCdTe detectors. We developed a camera to operate the FLIR AP1121 sensor using deep thermoelectric cooling and up-the-ramp sampling to minimize noise. We measured a dark current of 163 e- s[superscript -1] pix[superscript -1], a read noise of 87 e- up-the-ramp, and a well depth of 80k e-. Laboratory photometric testing achieved a stability of 230 ppm hr[superscript -1/2], which would be required for detecting exoplanet transits. InGaAs detectors are also applicable to other branches of near-infrared time-domain astronomy, ranging from brown dwarf weather to gravitational wave follow-up.