WAVE-FRONT CONTROL USING LIQUID-CRYSTAL DEVICES

We report on complete wave-front control with amplitude- and phase-mod ulation liquid-crystal devices (LCD's). A twisted nematic device is us ed for amplitude modulation, and an electrically controlled birefringe nt device is used for phase modulation. Because the LCD's are opticall y coupled with afocal optics and are driven by individual LCD driver c ircuits, the amplitude and the phase can be controlled two dimensional ly and independently. Complex amplitude data are calculated, and on-ax is computer-generated holograms are directly recorded. Furthermore, we discuss LCD performance requirements for high-quality reconstruction.