Silicon vidicon system for measuring laser intensity profiles

A silicon-target vidicon and minicomputer system providing rapid recording, readout, and processing of laser beam intensity profiles is described. Results are presented for 150-psec, 1064-nm neodymium laser pulses. Use of a thick, neutron-transmutation-doped silicon target reduced spatial sensitivity nonuniformities and coherent interference modulation. Modifications of commercial cameras to provide linearized output and timing control are described. The vidicon signal is recorded in a video disk recorder, digitized, and stored on a magnetic disk. Selected 1-D profiles and color isointensity whole beam profiles are available on CRT displays. Using a PDP-11 computer, the beam is analyzed to yield a peak energy flux within 100 sec after the laser pulse. The performance of the vidicon system is compared with photographic film techniques. Results show a sensitivity uniformity of succeeds, equals93% peak to peak over a target distance of 9.6 mm, linear dynamic range of greater, similar20, and absolute flux agreement within +/-10%. The system is useful for other laser wavelengths and pulse durations as well as for nonlaser applications.