Optical Logic Gates Using Ferroelectric Liquid Crystals

Ferroelectric liquid crystal (FLC) compounds are investigated for use in optical parallel processing. Spatial light modulators using the smectic C phase FLC's show better contrast ratio, faster switching speeds, and lower cost than twisted nematic liquid crystal spatial light modulators. In this paper we present measurements of characteristic parameters of FLC's, and demonstrate a new optical logic gate capable of performing fourteen Boolean logic operations using single cell FLC devices with photographic masks as inputs. The XOR and XNOR Boolean functions can be achieved by cascading together several optical logic gates. Recent results using 32 x 32 FLC matrix arrays demonstrate an OR gate which has programmable inputs.