High performance spatial light modulators for terahertz applications

We demonstrate large-contrast, low-crosstalk, low-power, and broadband spatial light modulators (SLMs) for operation at terahertz (THz) frequencies. The electro-thermally activated SLMs rely on the insulator–metal-phase transition of two VO2 thin films deposited on opposite sides of a sapphire substrate. We validated the effectiveness of our approach by fabricating and testing 2×2 pixel SLM prototypes. Record high amplitude modulation depth of 96%, −30 dB pixel-to-pixel crosstalk and precise THz transmission control was determined for the fabricated SLMs over a broad range of THz frequencies. Raster scanning THz transmission revealed excellent pixel uniformity with very large on/off contrast. These attributes are fundamental for high-contrast THz imaging and spectroscopy applications.