Second-harmonic generation in nanophotonic PPLN waveguides with ultrahigh efficiencies

摘要

We demonstrate second-harmonic generation in periodically poled lithium niobate nanophotonic waveguides with normalized conversion efficiencies up to 2600%/W-cm^{2. We achieve a 53% conversion within a 4-mm long waveguide at a pump power of 220 mW.}