Abstract: A Michelson-type self-aligning interferometer utilizes a laser to produce an output beam of light that is split into signal and reference beams. The signal beam is directed through a Bragg-cell, for heterodyne detection, and a beam expander, for facilitating target acquisition, toward a retroreflector located on a target body. The signal beam is thereby reflected back through the beam expander and Bragg-cell toward the resonance mirror of the laser, and is now shifted in frequency by 2.OMEGA.. The returning signal beam remains co-linear with the output beam since it returns over the same path and through the same optical elements, especially the laser resonance mirror. Thus, the interferometer can accommodate a significant amount of component misalignment without loss of operation. The signal beam, once reflected from the resonance mirror of the laser and partially reflected by the beam splitter, is co-linear with the reference beam.

Abstract: A charge controlled adaptive-optics system is disclosed for correcting phase distortion in a wavefront of a propagating optical wavefront in real time. In a preferred embodiment a selectively deformable piezoelectric mirror receives an incoming distorted optical wavefront and reflects it to a lenslet array optical sensor. The sensor generates a large plurality of focused light points, the offset positions of which represent wavefront tilts at a plurality of locations on the distorted wavefront. A misalignment calibration system calculates a plurality of calibration signals representing aberrations in the mirror surface and the sensor, and converts the signals into a plurality of representative light rays of varying intensity. The light ray are then superimposed on the light points to form a plurality of calibrated light points, which are then input to an electron-beam generating system.