Threshold Sensitivity of the Mid-IR Sensors

Abstract

The report presents expected threshold characteristics of photosensors based on uncooled mid-infrared (2-5 μm) A3B5 photodiodes characterized by a fast response time (tens of ns) and high detectivity (10-10-10-11 W / cm2√Hz), but low (from few Ω to kΩ) shunt resistance. The calculations are based on the noise analysis of the sensors using various types of photodiodes and operational amplifiers. The proposed "vector" noise description method was used to optimize the A3B5 sensor design elements and to estimate the value of their threshold sensitivity at the required speed of operation. As an example of promising A3B5 sensor application in the measurement technologies, the metrological characteristics of these sensors estimated for infrared thermometry (pyrometric sensors) are presented. It is shown that they are superior to known analogues in the low temperature detection limit (from 0 °C) and high response time (a few microseconds), while maintaining the high accuracy (at 1%) at low temperatures.