LATEST PHYSICS in the Physics Department:

1998:
Profesor Low Kum Sang and several coworkers have succeeded in looking at wave effects like diffraction for electromagnetic waves using only geometrical optics which only involves ray tracing. This is carried out using a generalised eikonal formalism and is done in linear and nonlinear dispersive media. The direction of the wavefront bends to give the effect of diffraction. Huygen's principle is no longer needed.
See: B. C. Quek et al., J. Opt. Soc. Am. A 15 (1998) 2720; S. C. Yap et al., J. Opt. Soc. Am. A 15 (1998) 2725.