A spatial light modulator (SLM) is a key device that enables a coded aperture imaging technique to extract spectral signature for remote detection and identification without platform motion. The SLMs offer a way to carry out spectral imaging with reconfigurability, which allows signature detection against a spectrally cluttered background. Liquidcrystal display (LCD) arrays and digital micro-mirror devices (DMDs) are used to implement the spatial light modulators, and there are shortcomings in infrared (IR) applications. Here, we report on a new solid-state SLM modulator device operating in the infrared range with SbTe-based phase change material. The SLM leverages a dramatic change (<2) in refractive index of SbTe phase change material within most of the IR bands, depending on their phase (amorphous versus crystalline).