Robust Evaluation of Long-Term Stability of an InAs/GaSb Type II Superlattice Midwave Infrared Focal Plane Array

Abstract

The temporal stability of the image quality of an infrared focal plane array (FPA) is one key parameter to consider for high performance imaging applications. It is generally evaluated through Residual Fixed Pattern Noise (RFPN) measurements realized after a two-point correction (TPC) and bad pixels exclusion. However, the effect of random telegraph signal (RTS) on temporal stability has never been quantified, the intermittent blinking of RTS pixels making measurements inherently complicated. In this paper, we propose a novel protocol and a novel data processing technique to fully characterize the temporal stability of an infrared FPA, thanks to simultaneous RFPN and RTS noise measurements. Using a robust statistics based on Median Absolute Deviation (MAD) leads to a more trustful RFPN evaluation, unaffected by the bad pixels exclusion step. This new protocol can be applied to any FPA technology, cooled or uncooled, operating in the [3-14µm] spectral domain. We chose to use a Type-II superlattice (T2SL) midwave infrared FPA integrated in a cryocooler at 80K. We show that the long-term stability of this 320x256 pixels FPA is excellent. The RFPN only slightly increases over 77 days, using a TPC that has been calculated on the first day of the measurements campaign. A simple offset update, compatible with operational contingencies, can further improve the temporal stability of this FPA. Only 0.3% of the pixels were affected by RTS noise at some moment. Those blinking pixels don't affect the RFPN evolution, which is a very encouraging result for T2SL detector technology.

Dark current behaviour of type-II superlattice longwave infrared photodetectors under proton irradiation

“…During the last ten years, an InAs/GaSb type-II superlattice (T2SL) photodetector has emerged as a complementary IR technology to those already well established [2,3], in particular for space applications by exhibiting an excellent radiometric stability over time [4]. However, the T2SL suffers from a weak Shockley-Read-Hall (SRH)-limited minority carrier lifetime (typically 30 ns in the LWIR [5]), inducing high dark current values.…”

On-Board Flickering Pixel Dynamic Suppression Method Based on Multi-Feature Fusion

“…The blind pixel detection method can be classified into two categories. The first category is the calibration-based method [6][7][8], which uses the blackbody to obtain uniform reference images and detect blind pixels by comparing each pixels' response rate, deviation factor, noise statistics, and other properties. This method is easy to implement and has a good detection effect for constant blind pixels.…”