Improved low frequency stability of bolometric detectors

An ac bridge readout system has been developed that greatly improves the low-frequency stability of bolometric detectors. The readout can be implemented with a simple circuit appropriate for use in space applications. A matched pair of detectors was used in the readout to achieve system noise within a factor of two of the fundamental noise limit of the detectors at frequencies as low as 10 mHz. The low-frequency stability of the readout system allows slower, more sensitive detectors to be used in many applications, and it facilitates observing strategies that are well suited to spaceborne observations.