Semicylindrical microresonator: excitation, modal structure, and Q factor

The semicylindrical microresonator with relatively simple excitation with a plane wave is studied. The resonator is formed on the base of the dielectric/metal/dielectric structure, where the wave energy penetrates into resonator through a thin metal layer and stored in a semicylindrical dielectric with high permittivity. The proposed microresonator combines features of Fabry-Perot and Whispering gallery mode resonators. Dependence of radiation losses on the radius and materials are estimated by theoretical analysis, while excitation by a plane wave is shown via numerical analysis. The quality Q-factor of the resonator can achieve up to 104, at a radius of a semicylinder of several microns.