Single mode lasing from a coupled asymmetric microcavity

Microdisk lasers (MDLs) that operate on whispering gallery modes (WGMs) have very high Q values because light propagates via total internal reflection along the cavity perimeter and forms closed loops. WGMs have a free spectral range (FSR) that is inversely proportional to the resonator size. A typical circular shaped MDL emits light uniformly in the plane of MDL with densely combed longitudinal narrow linewidth spectral lines, its effective linewidth covers at least several FSR and is thus not dasianarrowpsila. Special techniques have been used to generate single frequency laser from microcavity lasers, which include reducing cavity size to a few micro-meters, and using single frequency pump source. These techniques obviously lack the general possibility of integrating microcavity laser with other components in optical circuits.