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The positions and width of the fringes in a binary synthetic hologram are determined by the points at (x,y) that satisfy -q/2

Diffraction gratings are used in many optical systems as beam splitters. In these applications the diffraction grating must (1) have high diffraction efficiency and (2) produce uniform intensities in the central block of diffracted beams. High diffraction efficiency is attained by making the grating a phase grating. In this paper we discuss in some detail the use of pulse width modulation (PWM) and pulse position modulation (PPM) to create grating structures that produce uniform central diffracted beams. By using these modulation techniques and proper phase relief for the grating, the diffraction grating can have a diffraction efficiency of 70% or more. Some examples of multiple beam diffraction gratings produced by using PWM and PPM are shown.

A new laser grating scanner concept with attractive capabilities is described. The grating used in this scanner is a computer-generated hologram. The constructional parameters of this type of computer-generated hologram are discussed. In addition to achieving a laser beam deflection, the computer-generated hologram can correct the curvature of the scanning beam. Experiments demonstrating the feasibility of this type of scanner in a drum and disk configuration are presented. Realization of two-dimensional scan patterns using computer-generated holograms is illustrated by experimental results.

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