A crystalline silicon 1.1-20 micron spatial light modulator has an X-Y array of p-i-n pixels which are selectively foward biased at low voltages to induce substantial phase shifts in the optical wavefront, by the dual injection of holes and electrons through the silicon body and parallel to the light...http://www.google.de/patents/US5157538?utm_source=gb-gplus-sharePatent US5157538 - Silicon spatial light modulator
