Spatial amplitude and phase modulation using commercial twisted nematic LCDs

TL;DR

This paper introduces a method to achieve independent spatial phase and amplitude modulation of laser beams using commercial twisted nematic LCDs combined with spatial filtering, enabling precise control even with imperfect modulators.

Contribution

The authors demonstrate a novel technique that combines four pixels into a superpixel for independent phase and amplitude control using standard LCDs, without special device requirements.

Findings

Successful experimental demonstration of independent phase and amplitude modulation.

Effective control achieved with commercial twisted nematic LCDs.

Technique tolerates imperfect spatial light modulators.

Abstract

We present a method for full spatial phase and amplitude control of a laser beam using a twisted nematic liquid crystal display combined with a spatial filter. By spatial filtering we combine four neighboring pixels into one superpixel. At each superpixel we are able to independently modulate the phase and the amplitude of light. We demonstrate experimentally the independent phase and amplitude modulation using this novel technique. Our technique does not impose special requirements on the spatial light modulator and allows precise control of fields even with imperfect modulators.