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${}^{-1}$ pix${}^{-1}$, 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${}^{-1/2}$, 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.

Submitted to Proc. SPIE, Astronomical Telescopes + Instrumentation (2014)