Multimode resonances in square-shaped optical microcavities

Square-shaped two-dimensional optical microcavities (mu -cavities) were investigated for possible applications as filters for dense wavelength-division multiplexing, Multimode cavity resonances were observed in the elastic scattering of approximate to 200-mum square-shaped mu -cavities in fused silica. Based on a two-dimensional k-space representation, we accounted for the multimode spectrum by different normal modes with rays confined by total internal reflection. The cavity-mode trajectories need not be closed after each round trip. Single-mode spectra are expected from smaller square-shaped mu -cavities. (C) 2001 Optical Society of America.