Optimized phase quantization for diffractive elements by use of a bias phase

Many applications of diffractive phase elements involve the calculation of a continuous phase profile that is subsequently quantized for fabrication. The quantization process maps the continuous range of phase values to a lim ited number of discrete steps. We report our observation of the influence o f this quantization process on the performance of mode-selecting diffractiv e elements and show that the quantization process produces significantly be tter results by use of an optimized bias phase. In principle this process c an be employed to a greater or lesser extent in any quantization process. ( C) 1999 Optical Society of America.