Ray-optics analysis of inhomogeneous optically anisotropic media

When the optical behavior of light in a medium depends on the direction in which light is traveling, the medium is called optically anisotropic. Light is an electromagnetic wave and in this thesis, we discuss the electromagnetic theory on optical anisotropy. We do this with the assumption that the wavelength of light approaches zero. The field in optics in which this approach is applied is called geometrical optics. Then the wave character of light is not taken into account. In addition, we define a light wave as a set of rays, each with a certain direction and polarization state. The polarization state of a light ray defines the direction and the phase of the oscillating electric field of the light. In general, the light path of a light ray in an anisotropic medium depends on both the direction and the polarization state. The study of optical systems by means of calculating ray paths of polarized light rays is called polarized ray tracing. Optical anisotropy in the geometrical-optics approach is a classical problem, and most of the theory has been known for more than a century. Since the 1970s optical anisotropy is frequently discussed in the literature due to the rapid advances in liquid-crystal applications, such as the Liquid-Crystal Display (LCD). Liquid crystal is attractive for high-tech applications since it has the material properties of a fluid and the optical properties of an anisotropic crystal. Moreover, the optical properties of liquid crystal can be controlled with electric or magnetic fields. In the past few years Philips Research has had several activities in the field of liquid crystal. Novel liquid-crystal devices and applications have been investigated and developed into proof-of-principle demonstration models. In 2004 Philips Research introduced an auto-stereoscopic display technique based on liquid-crystal technology. Other examples are liquid-crystal-based backlight architectures for LCDs, liquid-crystal lenses and beam steering devices. Most
TNW Optics Research Group
Delft University of Technology