Open Collections

Finite difference time domain modeling of diffraction losses in dielectric structures having translational symmetry

University of British Columbia

This thesis concerns the quantification of the prism light guide's fundamental diffraction limit, by means of numerical simulation. A new technique is developed to model the intrinsically 3D problem of an off-axis incident plane striking the prism light guide wall, in a reduced 2D treatment which retains all the physics of the original problem. In order to study this system, a computer code is developed based on the Finite-Difference Time-Domain algorithm, and its accuracy is verified by modeling test systems having known analytical solutions. The system is then applied to the dimensionally reduced prism light guide problem. As expected, the numerical calculations show an approximate linear relation between the diffraction loss per reflection off the prism light guide wall A and the ratio of radiation wavelength to prism size, — . Previously, the ratio of a X loss fraction to — was unknown, and this work for the first time establishes the a ratio to be approximately 0.75, which is an encouraging result which means that prism light guides can be improved considerably relative to those manufactured today. A video tape showing the animation of diffraction process is provided. Two methods are then presented to attempt to reduce the diffraction losses. The first, re-shaping of the corners of the prisms in the prism light guide wall, does not show any improvement. However the second, in which metallic reflectors are placed just outside the prism corners, does reduce diffraction loss to some extent. This suggests that further research work is warranted to further reduce diffraction losses in a Prism Light Guide.

Thesis/Dissertation

application/pdf

2009-03-11

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

http://hdl.handle.net/2429/5897

Physics

University of British Columbia

UBCV

DSpace