Reflective spatial light modulator with high spatial frequency border

A spatial light modulator having a plurality of individually-addressed phase-modulating pixels, wherein the pixels are configured to reflect and modify phasing of a beam of coherent light incident on the spatial light modulator to produce reflected light, this phasing controlled to steer the reflected light into a target range of angles, the spatial light modulator comprising:

• a substrate;
• a first array of individually-addressed reflective phase modulation pixels on the substrate having a first spatial frequency of N and configured to apply a plurality of phase modulations to a central portion of the beam;
• a first biasing circuitry coupled to the first array of pixels that biases the first array of pixels to impart phase delays to the central portion of the beam, thereby steering a majority of the central portion of the beam within the target range of angles;
• a second array of border pixels on the substrate arranged to surround the first array of pixels, the second array of pixels having a second spatial frequency of N′, where N′>N;
• a second biasing circuitry coupled to the second array of pixels that biases pixels of the second array of pixels to impart M different phase delays, thereby steering a majority of the peripheral portion of the beam outside the target range of angles, where M is a number of different groups of pixels in the second array.