Optical resonances in dielectric microspheres for transverse magnetic wave

Optical resonances for Transverse Magnetic (TM) wave based on Whispering Gallery Modes (WGM) have been presented with comprehensive mathematical formulations. The present study is characterized both theoretically and experimentally by considering the fact that the size parameter of the dielectric microspheres is very large at optical wavelengths. An asymptotic expression has been developed based on electromagnetic theory for large size parameter. The developed expressions for optical resonance condition of TM wave are very simple and can accurately characterize resonances in dielectric microspheres. The theoretical development is mathematically robust and significantly less complicated than existing approaches based on quantum physics presented in the literatures. The theoretical result of size parameter for consecutive morphology dependent resonance (MDR) peaks is validated by experimental data. The comparisons are shown to be very accurate for large size parameters.