Ultralow noise preamplifier for high impedance infrared bolometer

Abstract

An ultralow noise preamplifier has been designed for use with a high impedance infrared bolometer. The preamplifier makes use of an ultralow noise field effect transistor connected to an operational amplifier in a cascode configuration. A simple regulator circuit allows the unit to be powered by any laboratory dc power supply instead of using special low noise batteries. The equivalent input noise, measured at room temperature with the input short circuited, is 1.5 nV/Hz^1/2 rms at 80 Hz.