Laterally emitted surface second harmonic generation in a single ZnTe nanowire

We report a direct observation on the laterally emitted surface second harmonic generation (SHG) in a single ZnTe nanowire. The highly directional surface SHG radiates vertically to the nanowire growth-axis with a high conversion efficiency of 5 × 10^-6 and a low divergence angle of 4. Polarization state, emission intensity, and direction of the surface SHG are found to be dependent on the polarization of the pumping laser, which is further confirmed by numerical simulations. The laterally emitted surface SHG with a high efficiency and low divergence angle has great potential for short-wavelength nanolasers, nonlinear microscopic imaging, and polarization-dependent photonic integrating.