Surface plasma wave induced second-harmonic generation on a metal–semiconductor interface: effect of self-focusing of a laser

The effect of the self-focusing of a laser on second-harmonic generation (SHG) induced by the surface plasma waves (SPW) over the metal-semiconductor interface has been investigated. The nonlinear interactions of a laser with metal generate SPW. These high-amplitude waves could penetrate through plasmonic entities of metal and can interact with electrons of a semiconductor leading to SHG. The behavior of the beam width parameter for different metals has been analyzed. One may notice that the beam width parameter shows periodic variation with the distance, but the amplitude shows maxima in the regions of the low beam width parameter. The focusing accompanied by the increase in SHG amplitude is found to be better for the Cu-InSb interface as compared to the Ag-InSb and Al-InSb ones. The present work puts forward the metal-semiconductor interface as a good choice for SHG.