Feedback control system for laser beam alignment

Abstract

A fully automatic feedback control system of alignment for a pulsed infrared laser beam (10 ns pulses, 10 Hz repetition rate, 1064 nm wavelength) was developed and tested. The stability of laser beam is limited by several factors, such as the most common being temperature changes and mechanical vibrations inside the laser and along the long distance optical route. This new feedback control system could correct these drifts of the laser traverse route in time. The solution is based on using CCD sensor as laser spot image acquiring device aimed to capture the information of laser pulses with a certain frequency and serve motorized mirror mount controlled in according to the feedback information of the spot image by a computer simultaneously. The paper solves the problem of synchronization between laser pulse and camera with measurement method to capture whole images, restrains background noise and assures the image of best effect. As a result, the two axes motorized mirror mount could be corrected automatically based on the drift of laser beam spot centroid after every laser pulse.