Sub-bandgap transverse frequency conversion in semiconductor nano-waveguides

Transverse frequency conversion in the sub-bandgap spectral region is investigated in semiconductor nanowires and nanoribbons by using CW lasers with pump power less than 1 mW. It is found that the properties of the emissions are strongly dependent on the cross-sectional geometries and the surrounding media of nano-waveguides. Compared with birefringent approach, transverse frequency conversion shows lower divergence angles, higher polarization, and more tunable spatial distribution.