Studies of optical systems containing liquid crystals and holographic optical elements

Optical retarders are generally produced from homogeneous crystals or stretched polymer films. The birefringence and dispersion properties of those films are primarily controlled by the molecular structure of the material. Unfortunately, the resulting properties may not be what are desired for a particular application. For example, in the case where retardation films are designed to compensate liquid crystals for improved display devices, the dispersion characteristics of the retarder often do not match that of the liquid crystal. However, retarders based on form birefringence have the potential for greater control of material properties, such as birefringence and dispersion.; The transmission of electromagnetic waves through both slanted and unslanted volume holographic retarders, in the form birefringent regime, is calculated. The material parameters of the holographic retarders are varied and the resulting effect on birefringence is presented. Significantly, it is shown that the dispersion properties of these retarders can be adjusted over a large wavelength range. Further, the design of a retarder with improved properties that ideally compensate the optical properties of a liquid crystal layer is shown. A vertically aligned (VA) LCD is compensated using unslanted holographic retarders in the form birefringent regime. A twisted nematic (TN) LCD is compensated using stacked, dispersion matched, slanted holographic retarders. The Berreman method is ideal for calculating the transmission or reflection of electromagnetic waves through unslanted volume holograms since they are composed of layers of varying index.{09}However, slanted volume holograms require a calculation method that will allow index variations at some angle to the hologram's normal; therefore, a method for calculating light propagation through a system of numerous different stacks, which do not have parallel layers of constant permittivity tensor, is developed to allow these calculations.; This new extension of the Berreman method is also used to calculate the reflection of electromagnetic waves from both slanted and unslanted volume holograms, in the Bragg regime. Since the Berreman method allows for an arbitrary dielectric profile, holographic reflectors are evaluated with square, sinusoidal, or irregular morphologies. The model is applied to the specific case of chirped photopolymer gratings. The Berreman method also allows for uniaxial layers, which permits the investigation of birefringence in the hologram layers. A slanted holographic reflector is included in a reflective, single polarizer, low twist liquid crystal display (LCD), designed for active matrix. The LCD is optimized for the off axis angle of the holographic slanted reflector. A slanted holographic reflector is also included in a reflective, single polarizer, high twist LCD, designed for passive matrix. The high twist display is optimized using a new method that considers the variables of the LC layer without the added variables of the polarizer and retarders. This method calculates the polarization states through out the LCD and compares those polarizations to find the optimum display. This method is more generally applicable then previous optimization methods and does not require any additional changes when considering a holographic slanted reflector (HSR) in place of a plane mirror.