Phase-only SLMs for optical pattern recognition and security systems

Original experimental techniques for obtaining the phase-only modulation and the complex amplitude modulation with the commercial twisted nematic liquid crystal televisions (LCTV) are described. The techniques are based on the Jones matrix theoretical analysis. We use the programmable phase-mostly LCTV to optically implement the phase-only matched filters, phase-only circular harmonic filters, phase-only synthetic discriminant functions and the adaptive composite wavelet matched filters for pattern recognition. We also implement the phase-only computer generated holograms, speckle-free kinoforms and optical kinoform encryption using random phase encoding for security applications.