Efficient second harmonic generation between photonic and plasmonic modes in a tunable transparent conducting oxide waveguide

Efficient second harmonic generation (SHG) in a nonlinear transparent conducting oxide (TCO) stripe waveguide that incorporates an organic polymer is theoretically investigated. The phase match condition between the fundamental photonic mode at the second harmonic and the fundamental long-range plasmonic mode at the fundamental frequency can be satisfied by dynamically or statically tuning the free carrier concentration of the TCO. The theoretically generated signal reaches its maximum up to 56.4 mW at a propagation distance of 34.8 μm for a pumping power of 1 W. The corresponding normalized conversion efficiency of the phase-matched SHG is up to 4.65 × 10³ W^-1 cm^-2.