Second-Order Nonlinear Susceptibility Enhancement in Gallium Nitride Nanowires

We report the second-harmonic generation (SHG) from single GaN nanowire. The diameter of the GaN nanowire varies from 150 to 400 nm. We present a model for the SHG process in the GaN nanowire; the analysis shows quantitatively that the SHG is dominated by its surface area. The effective (2). second order nonlinear optical susceptibility (chi((2))(eff)) increases as the diameter of the GaN nanowire decreases. For 150-nm diameter GaN nanowire, chi((2))(eff) reaches 136 pm/V.