Lowering of threshold conditions for nonlinear effects in a microsphere

Abstract
An explicit relationship between the Lorenz-Mie resonances and nonlinear optics of a microsphere has been found. We have constructed an approximate analytic method which allows an adequate assessment of the threshold for stimulated Raman scattering in microspheres. Systematic investigation of the characteristic equation, using approximate analytic expressions, reveals that not all modes have the same quality. Some resonances with very high quality correspond to a physical situation in which the spherical waves can be envisioned as whispering-gallery light waves that are totally internally reflected by the sphere boundary, without suffering almost any loss. © 1996 The American Physical Society.