Designer spectacles look great and we want the same for a virtual display. A curved wedge guide will be described that can transfer the virtual image from a projector near the ear round to the pupil of the eye. The eye-box is tiny but the plan is to steer it so as to follow the pupil of the eye and this will be done by shearing the holographic combiner. Ray-tracing predicts a field of view of 115° per eye and a resolution of 2000 pixels per radian at the fovea using pre-distortion in the projector. Guide tolerances are lax, image accommodation is variable and a few milliWatts suffice to steer the pupil.
The advent of nanolithographic techniques has enabled electrically-driven liquid crystal devices to be addressed
using nanoscale electrodes. Tiny periodic phase grating structures, which can now be realized, may find applications
in optical communications and displays devices. Introducing optical discontinuities in the nematic liquid
crystal (NLC) material will enable these structures to act as photonic band gap devices. This paper addresses the
properties of band gap structures formed by NLC discontinuities using a 10micron thick homeotropically aligned
NLC. It demonstrates how the position of the optical discontinuities may be altered by a symmetric voltage pattern
and thus tune the photonic band gap.
Phase holograms can, in principle, route light with zero photon loss. This property makes them ideal for applications with tight power constraints such as free space interconnects and optical tweezers. Both applications require that the deflection angle is varied accurately and smoothly over a certain range. For example, in a free space switch, the output would be a single mode fibre with core diameter of 9μm and the beam has to be centred accurately on it. If an adaptive link is used the beam will be scanned near the output and the optimum position will be determined. Any quantisation effects on the deflection angle may cause instabilities in the feedback loop of the link. In optical tweezers the quantisation effects on the deflection angle will cause the particle to move in discrete steps. This may release the particle from the optical tweezers due to the large acceleration. The quantisation effects on the deflection angle may be difficult to observe because of the very small changes involved. However, these effects can be very important. In this paper we derive the quantisation effects introduced to the deflection angle due to hologram quantisation. We evaluate the minimum number of pixels required in order to achieve a certain resolution on the deflection angle, and finally we suggest methods for enhancing the performance of the hologram by taking into account these effects.