Exact solution to simultaneous intensity and phase encryption with a single phase-only hologram

TLDR

A phase‑only hologram transforms an optical transverse spatial mode through phase encoding and intensity masking, and accurate control of the field depends on the encoding method, since intensity masking alters amplitude and phase. The paper proposes a method to encode both amplitude and phase into a phase‑only hologram, enabling exact control of spatial transverse modes. The method corrects unwanted phase shifts by adjusting the phase encryption, and its accuracy is experimentally verified on generating and detecting transverse spatial modes in mutually unbiased bases of dimensions two and three. The method accurately generates and detects transverse spatial modes in mutually unbiased bases of dimensions two and three.

Abstract

A phase-only hologram applies a modal transformation to an optical transverse spatial mode via phase encoding and intensity masking. Accurate control of the optical field crucially depends on the method employed to encode the hologram. In this Letter, we present a method to encode the amplitude and the phase of an optical field into a phase-only hologram, which allows the exact control of spatial transverse modes. Any intensity masking method modulates the amplitude and alters the phase of the optical field. Our method consists in correcting for this unwanted phase alteration by modifying the phase encryption accordingly. We experimentally verify the accuracy of our method by applying it to the generation and detection of transverse spatial modes in mutually unbiased bases of dimension two and three.