F.B.P. Niesler, N. Feth, S. Linden, and M. Wegener

Opt. Lett. 36, 1533 (2011)

Abstract:

Previous second-harmonic-generation experiments on metallic split-ring-resonator arrays have been performed at fixed fundamental laser center frequency. Here, we perform nonlinear optical spectroscopy on a first set of samples, revealing pronounced resonances. Furthermore, to clarify the role of higher-order split-ring resonances, we perform additional experiments on a second set of samples in which the fundamental split-ring-resonator resonance frequencies are lithographically tuned, whereas the higher-order resonances are fixed. We find that the higher-order resonances merely reabsorb the second-harmonic generation, revealing the fundamental split-ring resonance as the nonlinear source.