Second harmonic generation in metal-LiNbO-metal and LiNbO hybrid-plasmonic waveguides.

Nanoplasmonic waveguides based on lithium niobate (LN) are shown to provide the light-matter interaction required for next-generation developments in nonlinear frequency-conversion nanostructures. Here, we numerically investigate second harmonic generation of a 1550 nm, 100 fs pulse in metal-LN-metal (MLNM) nanoplasmonic and LN hybrid-plasmonic (LNHP) waveguides. In comparison to a photonic LN waveguide, a 2.1 µm-long LNHP waveguide exhibits a conversion efficiency improvement of 11 times, whereas a 20 µm-long MLNM nanoplasmonic waveguide is shown to have a conversion efficiency of 1.1 × 10. The MLNM nanoplasmonic and LNHP waveguides have the potential to operate as sources of optical radiation for on-chip photonic systems.