U.V. Laser Beam Diagnostics using a Computer Controlled Video Frame Store System

Abstract

In the past the spatial intensity profile of a laser beam has been measured using such techniques as scanning pinholes, detector arrays and photography. This new system converts the Excimer beam into visible light using a glass fluorescer with a very small penetration depth giving a good 2D image of the beam. The fluorescence has been found to be linear over a wide range of input energy and is imaged by a CCD camera linked to the computer controlled video frame store. The digitised information is then computer processed to yield such results as the intensity profile along an arbitary line, peak fluence, the difference between two images and various statistical values. This new technique has been applied to beams with widely varying diameters including analysis in the focal region and in the early detection of damage in materials.