Manipulation of Light Using Slanted-layer Photonic Crystals

Manipulation of light in structures has great potential for real applications similar to the control of the flow of electrons in semiconductors. An example is photonic crystals that exhibit photonic bandgaps in which electromagnetic wave propagation in the bandgaps is forbidden. This can be used to bend light, similar to the use of waveguides. A simpler approach is to use slanted- layer structures in thin films (gratings). This book presents the fabrication of single- and double-slanted-layer structures in silver halide gelatin emulsions using a two-beam optical interference for the visible range. Light, with wavelengths in the bandgap of the layer structure, can be bent sideways or make a U-turn inside gelatin emulsion for normal incidence, depending on different slanted-layer configurations. The slanted- layer structure can be applied as in-plane input and output couplers to optical fibers and waveguides.