Optical second-harmonic generation with coupled surface plasmons from a multilayer silver-quartz grating
The paper reports a theoretical and experimental study of enhanced optical second-harmonic generation due to excitation of coupled surface plasmons from a thin silver grating bounded by two quartz crystals. With incident radiation from a Nd:YAG laser, diffracted second-harmonic generation in the n = 1, 0, and -1 modes is observed for the coupled surface plasmon fundamental modes. Nonlinear reflectance ratios calculated by using the reduced Rayleigh equations are in good agreement with the experimental results. Enhancement of the second-harmonic generation is limited by the scattering of the long-range surface plasmon mode in the thinnest silver films studied.