Thermal imaging quantum detectors, past, present, and (possible) future: HgCdTe vs competitors (Conference Presentation)

In any sensing application, the most universal performance parameter is the signal-to-noise ratio (SNR). Over time, application needs push high-performance thermal imagers toward their ultimate SNR limit – background limited performance (BLIP) – the best any imager can do. BLIP SNR is determined by random shot noise inherent in the scene itself. The noise (and thus the SNR) magnitude is the square root of the number of signal photons collected, requiring the best sensors to collect all available scene light and add no additional noise. Quantum photodiodes made from infrared semiconductors have proved to be the highest sensitivity thermal detectors, but their dark currents (which add noise but no signal) increase exponentially with temperature and so still require significant cooling to attain BLIP. Recent breakthrough results from Teledyne show that HgCdTe can attain much lower dark currents than previously reported leading to higher BLIP operating temperatures and approaching fundamental limits. This talk will focus on HgCdTe photodiodes which have the best demonstrated performance to date for devices either fielded or in development and will compare these devices to other semiconductors past, present, and (likely) future.