Optical second-harmonic response of an axially-symmetric medium under radially polarized excitation
We simulated optical second harmonic response, both surface and bulk, of axially symmetric media excited by tightly focused radially polarized fundamental beams. The modeling showed a highly localized character of second harmonic generation. We estimated decrease of overall second harmonic signal for defocusing of fundamental beam relatively to a sample’s surface. Radiation patterns of second harmonic waves were compared for different numerical apertures of a focusing objective, for different focus shift relatively to the sample’s surface and for surface and bulk second harmonic responses. The model developed is applicable for second harmonic generation by interfaces, films and poled glasses.