Quantization effects on the fields of electron-beam generated cylindrical zone plates.

Recently, various high-precision digital graphic systems have been used to generate patterns for diffractive and computer generated holographic optical elements. These plotting systems with submicron accuracy have a common drawback, namely, the patterns drawn have to be quantized. In this paper, the effects of pattern quantization on the optical beams are studied. Specifically, the fields of perfect cylindrical zone plates and cylindrical zone plates with quantized stripes are compared with that of conventional refractive cylindrical lenses. In particular, the effects of quantization on the width of and power in the main lobe and the level of the sidelobes are studied. The results are cast in terms of normalized parameters and are applicable in general.