FULL-RANGE, CONTINUOUS, COMPLEX MODULATION BY THE USE OF 2 COUPLED-MODE LIQUID-CRYSTAL TELEVISIONS

Switchable, continuous, complex-amplitude modulation is demonstrated w ith two cascaded, twisted nematic liquid-crystal televisions(LCTV's), both operating in phase- and amplitude-coupled modulation modes. The c ondition for full-range complex modulation is that one of the LCTV's m ust provide a a 2 pi-range phase modulation. A look-up table encoding method is proposed that permits the compensation of phase-amplitude co upling and nonlinearity in the two individual LCTV modulations. Experi mental techniques for determining the LCTV-device parameters, for maxi mizing the phase-mostly modulation range and the amplitude-mostly modu lation contrast, and for testing the complex-amplitude modulation are developed. Optical complex-amplitude Fresnel holograms are shown. (C) 1996 Optical Society of America