Velocity sensing interferometer (VISAR) modification

The VISAR (velocity interferometer system for any reflector) has become a common tool used in experiments where high surface velocities must be measured. A modification that uses previously wasted interferometer light to more than double output signals and to cancel noise is described. Laser power is used more efficiently, VISAR performance in the presence of intense target self-light is improved, and only two data signals are required instead of the usual three or four. Effects of changing light intensity and fringe visibility are eliminated using a novel detection system with a simplified solution for velocity.