Plasmon hybridization for enhanced nonlinear optical response

We report the plasmon hybridization between silver nanoprisms and a thin gold film as a means to tune the plasmon resonance and to achieve enhanced optical second harmonic generation. The hybridization enhances the second harmonic counts by nearly three orders of magnitude when varying the spacer layer between the nanoprisms and the gold film. Finite-difference time-domain calculations agree within a factor of 2 with the experimental findings in terms of the predicted enhancement factor. This plasmon hybridization approach is promising for future applications, including multi-photon lithography and nonlinear sensing using metal nanoparticles.