Terahertz Spatial Light Modulator Based on an Electrostatically Tunable Array of Large Micromirrors

We present a new type of terahertz spatial light modulator (THz-SLM) based on an array of large micromirrors. The electrostatically tunable micromirrors spatially modulate terahertz waves in a frequency range from 0.97 THz to 2.28 THz with a peak modulation contrast of 87% at 1.38 THz. The array consists of 768 micromirrors with each having a length of 220 μm and a width of 100 μm. The mirrors are grouped into 24 pixels. By application of a bias voltage, the pixels can be individually switched between a reflecting and scattering state, which allows spatial modulation of terahertz radiation.