Optical microcavities

Abstract

Abstract Optical cavities or resonators having dimensions of the order of cube of the wavelength, are introduced with the definitions of DOM, mode volume, quality factor, finesse, and loss mechanisms in general. The simplest resonator structures, the FP resonator, Bragg gratings and mirrors, and ring resonators and their characteristics are presented next. Resonators working with whispering gallery modes, different structures used, and both ray-optic and electromagnetic theories to understand their operations are also discussed. The formation of photonic band gap in photonic crystal is illustrated by solving wave equation in a 1D periodic structure. The concepts are extended to 2D and 3D periodic structures, giving representative structures, typical dispersion relations, examples of photonic band gaps, and the methods to form waveguides. The micropillar structure is discussed in detail. Finally, a summary of different resonator structures, method of light confinement, values of Q, and sources are given.