The phase-only filter (POF) and binary phase-only filter (BPOF) have been shown to have high optical efficiency, good target discrimination, and virtually no sidelobes. We present a simple method of amplitude encoding the signal phase information. These new filters have most of the same advantages of a POF or BPOF so that amplitude modulating spatial light modulators or photographic film can be used.
Mary A. Flavin and Joseph L. Horner, "Amplitude encoded phase-only filters," Appl. Opt. 28, 1692-1696 (1989)