Miniaturized Displacement Sensor for Active and Adaptive Optics

We propose development of a miniaturized displacement sensor suitable in size and cost for mass-quantity use in adaptive and active optics applications. These sensors will be designed for the very high resolution required for precise control of local mirror shapes, segment location, and edge detection. The technology proposed uses a laser diode emitter/optics and position-sensing photodetector/optics receiver to achieve a non-contact absolute distance displacement sensor. The proposers manufacture displacement sensors based on this general technology already, but the size and cost preclude large quantity application to adaptive optics instruments. By using miniature replicated optics, small laser diodes, and the now available miniature position-sensing photodetectors, a hybrid sensor will be developed which can provide resolution to 1nm (0.04microinch) and accuracy of lOnm. The inherent high electrical bandwidth allows real time atmospheric turbulence correction in closed loop control systems. Objectives, effort, and results: A detailed prototype design is planned. Specifically, we will fabricate a demonstration model which measures +lOO micrometers displacement. Phase I addresses the sensor head and the linearization of its analog output. The current availability of the first generation digitization eleetronies makes the transition to Phase II low-risk.