Fast-response infrared phase modulator based on polymer network liquid crystal

We report a high birefringence terphenyl liquid crystal mixture, designated as M3, for infrared phase modulation with special emphasis on mid-wave infrared (MWIR). In addition to high birefringence, M3 exhibits excellent UV stability, modest dielectric anisotropy, and a very broad nematic range. The high birefringence enables a thin cell gap to be used for achieving a 2 pi phase change while maintaining a high transmittance (T > 98%) in the MWIR region. To achieve fast response time, we employed a polymer network liquid crystal using M3 with 2 pi phase change at lambda= 4 mu m and 3.6-ms response time. This response time is about 100X faster than that of a nematic LC phase modulator.