Abstract

We wanted to produce an array of parallel fringes of variable spatial frequency for use in signal processing experiments. Such fringes can be formed by interfering two coherent waves from orthogonally articulated galvanometer-mounted mirrors. However, because surface flatness on galvo-mounted mirrors is rarely better than one-quarter wave, it is virtually impossible to obtain, by direct interference of the waves, fringes that are straight. Holography provides a means for straightening such fringes. In holographic terms, we allowed the wave from one galvo-mirror to interfere with a holographic reconstruction of the same wave but with a slight relative tilt of the two waves. So long as aberrations are not excessive, the two aberrated but essentially identical waves interfere to produce straight fringes. Analysis and experimental results are presented.

© 1985 Optical Society of America