The photoelectro-chemical etching system of compound semi-conductor is disclosed. The system comprises a laser generator, a shutter to cut off laser beam, a laser beam chopper, a secondary high reflection mirror, a beam expander, a waveform generator, a chopper controller, a potentiostat to apply the reverse or forward voltage to the optical glass cell. Instead of applying the reverse-bias voltage to a semiconductor material, the reverse and/or forward voltage with a uniform pulse period is applied so that homogeneous and damage-free surface is obtained and etching process is made available in a more efficient manner.

In an optically phased array of multiple laser telescopes, the phasing between the telescopes is accomplished by sampling adjacent outgoing wavefronts. The two samples of each wavefront are then combined to form an interference pattern on a camera. This image is then converted to digital signals, employing an error signal representative of the phase difference. It is necessary that the telescopes be pointing in the same direction. This is assured by having each telescope associated with an optical sensor which produces an X or Y tilt error. The X or Y tilt error is corrected by the optical component referred to as the optical path difference adjustor (OPDA). A signal processing circuit is disclosed which receives X and Y tilt error signals, as well as phase error signals, and produces therefrom drive signals which correct and drive the OPDA in an array of multiple laser telescopes.

A plurality of light concentrators (12) each provide light over an optical fiber cable (23) to a single optical detector (25) in a non-imaging laser radar. Each light detector may comprise a single mirror (29) or a primary mirror (20) and secondary mirror (22). A transmitter (13) within the array may comprise the same configuration as the light concentrators (12) to deliver laser light from fiber optic cables (23, 30) or may comprise a primary mirror (35) with a large hole (38) that delivers laser light to a secondary mirror (37). The array provides a very rugged large aperture which is very short, and which can be increased without any increase in length.

Means including a single comparatively low-power laser and cooperative optics are disclosed for both designating and boresighting a comparatively high-power laser with an intended target object.

An apparatus and technique are described for phasing the outputs of a multiplier telescope array used as a laser transmitter. The technique uses samples of the transmitted beams to control optical path lengths through the separate telescopes so that the beams add coherently at the receiver. The phasing concept is applicable both to systems which provide inputs to the multiple telescopes by dividing a single laser beam and to systems in which the inputs to the telescopes and multiple, phase-locked laser beams. The approach is also compatible with single line and multi-line lasers, and it does not entail stringent alignment requirements. The concept uses a procedure to find the zero optical path difference condition and to effect fine control of the optical path lengths through the different telescopes. Algorithms are described for estimating the phase mismatch from focal plane measurements.