Mixing of Optical Modes in a Mechanically Perturbed Microstructure

Abstract

Theoretical investigations are carried out for optical modes in a mechanically perturbed (rotating) microstructure (microdisk). Whispering gallery modes with twofold degeneracy in the microdisk at rest split off due to the onset of rotation (the Sagnac effect). This rotation also excites a number of extra modes that appear to have developed from vacuum states in the microdisk at rest. These modes exhibit anticrossing and merging-regeneration phenomena as the rotation speed increases and consequently form a photonic band structure. The above phenomena can be explained in terms of optical mode mixing caused by coupling between different optical states through the angular momentum of rotation.