Multiplexing onto a spatial light modulator using random binary patterns

Abstract

.We introduce an approach for encoding a variety of independent outputs from a computer-generated diffractive optical element displayed on a spatial light modulator (SLM). In this approach, random binary 0-1 orthogonal patterns are multiplied to the different phase functions, effectively multiplexing the corresponding different outputs. We show experimental results with different examples of multiplexed phase functions. Additional functions can be multiplexed simply by adding more random binary patterns. We demonstrate the generation of up to eight different independent outputs. Although the technique was demonstrated years ago, nowadays it can be applied with high-resolution SLMs with a very large number of pixels, thus allowing for a larger number of multiplexed functions without significant degradation. Nevertheless, high-resolution SLMs are affected by pixel crosstalk caused by the fringing field effect. We show that the random patterns are quite sensitive to this effect, leading to a significant undesired DC order. Two alternative strategies to avoid this degradation and make the random multiplexing technique efficient are discussed.

Generating multiple polarization outputs using random binary patterns with cascaded spatial light modulators

“…For that purpose, we follow the random multiplexing approach, 15,16 which has been shown to be very effective in modern high-resolution SLMs. 13 The multiplexing technique is quite simple. We begin with a random binary pattern where each pixel is assigned a value of 1 or 0.…”

“…The method used to design the phase-only hologram displayed in SLM1 is a random multiplexing technique. 13 Thus, we are limited to the number of random binary patterns. As we increase the number of random binary patterns, the number of pixels available for each decreases.…”

“…The technique might also be affected by fringing effects, which affect SLMs having a greater number of smaller pixels. 13 Second, we rely on the fact that the different output beams have different spatial locations projected onto the SLM2 screen. For simplicity, we have generated delta function point objects.…”

“…For the generation of the multiple outputs, we apply a random multiplexing approach 13 that we recently demonstrated useful in high resolution displays. This random technique allows the generation of independent output beams with arbitrary locations in the Fourier transform plane.…”