Abstract: An apparatus, system, and computer-implemented method that correct for thermal drift in one or more optical elements in an optical device and maintain high precision accuracy of the optical device during extreme temperature changes. The apparatus includes an optical device having an optical element configured to direct or reflect a light beam, a pivot support configured to hold a portion of the optical element and facilitate motion of the optical element in multidimensional space, a controller configured to determine a displacement of the optical element due to thermal drift and generate an actuator drive signal based on the amount of the displacement, and an actuator configured to receive the actuator drive signal and counteract the thermal drift by moving, in cooperation with the pivot support and in response to the actuator drive signal, the optical element by an inverse amount and direction of the displacement of the optical element.

Abstract: The apparatus is a thermal detector which uses an active detector element and a compensator detector element, particularly in a voltage divider configuration. Radiation from a scene of interest impinges on the active detector element and radiation from an electronically modulated light source impinges on the compensator detector element.