Abstract

The efficiency of second harmonic generation for very narrow beams with diameter of few wavelengths is limited by two basic physical mechanisms: 1) the diffraction which will give rise to a broadening of both fundamental and second harmonic waves leading to a decreasing of their top intensities and eventually, of their nonlinear coupling; 2) the phase mismatch since all Fourier components of the narrow parametrically beams can never be simultaneously phase matched.

© 2009 IEEE