LWIR heterodyne HgCdTe detectors

Abstract

Single element and linear array photodetectors operating in heterodyne mode for CO₂ laser radiation detection have been developed and investigated. P-type mercury cadmium telluride (MCT) crystal with x=0.21 composition and hole concentration 1x10¹⁶ cm^-3 at T=77K were used as substrates. The p-n junctions in p-type MCT were formed by ion implantation. Detector was packaged in metal-glass dewar together with preamplifier. Cooling was performed by liquid nitrogen. Single-element heterodyne detector with p- n junction area 300X300 micrometers operates at frequencies up to 100 MHz. The noise equivalent power (NEP) at 10,6 micrometers wavelength is equal to 5x10²⁰ W/Hz for an applied local oscillator power 0,5 mW. 10-element photodiode linear array heterodyne detector been developed and investigated.