Development of a Computer Generation Holography for Generating Square Matrix Light Spots Applied to the Laser Patterning System

Abstract

A computer generation holography (CGH) is proposed herein to synthesize square-matrix light spots. Such a design of CGH is possible by reducing the 2-D problem to two 1-D problems. The both 1-D CGHs are designed with the conjugate-gradient method and verified with the Fresnel-Kirchhoff diffraction theory. This quantized 8-levels CGH is fabricated by using optical contact lithography and reactive-ion etching techniques. Measurement demonstrates that the fabricated CGH has the desired optical function, i.e., it forms square-matrix light spots in the image plane at a distance of 40 mm from the CGH. The developed CGH can be applied to the laser patterning system by optical projection and direct etching.