Abstract

Since high resolution recording materials are not readily available in the infrared and laser diodes do not have a sufficient coherent length, it is difficult to make an infrared hologram for the LD directly. An infrared hologram for a simple object can be easily calculated by a computer. If the hologram is large and the spatial frequency is high (say, more than 1000 lines/mm), it is still an elaborated process to generate these holograms by an electron beam machine. Also because of the long writing time required for the hologram, the electron beam and the translation stage stability must be carefully maintained. The former is often affected by the static charge built up and the latter by temperature changes and mechanical vibrations. In this paper we describe a different approach to make the hologram. We first create a CGH for a visible wavelength for which high resolution recording media are available. The CGH is then used as the object to make the final IR hologram using visible wavelength. The CGH is designed in such a way that the wavefront distortion is precompensated. The CGH is drawn by a personal computer system which includes an MP 1000-01 plotter.

© 1986 Optical Society of America