An analysis and an optical model for the polarization optics of a 3D display system based on two LCD monitors in an "open book" configuration and a beam combiner (BC) are presented. Calculations of the angle of incidence (AOI) distributions for likely display-observer configurations and an estimate of the range of AOI for which the BC should be optimized are reported. Experimental data for commercial BCs is presented and analyzed in the [RS, TP] unit square. A first order model is developed to calculate the effect of the BC optical properties on the stereo channels' brightness balance, system light efficiency and crosstalk. The model predicts that a significant reduction of the crosstalk can be achieved by a uniform rotation of the analyzers.
Optical variable pigment technologies for markings and inks have increased in use as overt protection methods for document and product security. These technologies use optical reflective effects including interference technologies that create angular dependent color changes. Novel developments in different inorganic and organic pigments offer potentially new optical performance for both overt and covert security applications. These developments may lead to unique signature pigment formats that can verify origin and authenticity. Cholesteric Liquid Crystal (CLC) pigment approaches utilize both angular dependent color flop and the unique polarization properties to potentially develop markings with both overt and covert detection mechanisms. Continuous improvement in these technologies may lead to new visible and non-visible applications that when integrated with the graphic design will provide novel protection and graphic impact.
We report on the correlation between features of the molecular structure of polyphenyls and the measured parameters of optical limiting: limiting threshold and clamped output. Optical limiting in these materials is mainly due to a strong light scattering (third order negative nonlinear effect). We show that in many simple cases the limiting threshold decreases with increased conjugation length, linearity, planarity and with the substitution of acceptor/donor end groups. The UV spectra and the wavelength dependence of the limiting parameters suggests that a two photon absorption mechanism is necessary for a low threshold and efficient light scattering.
We report the characteristics of a strong 3rd order negative nonlinear effect in the nematic and smectic A liquid crystal phases as well as in the isotropic phase. Limiting is achieved as a result of a strong light scattering effect with some contribution from nonlinear absorption. We used an optical limiting setup to measure the limiting threshold and clamped output parameters. We present data regarding the dependence of these parameters on polarization direction, liquid crystalline order and alignment, depth of focus into the liquid crystal layer, cell thickness and temperature. We also discuss the temporal behavior of the limited pulses.