Figure 2
From: Origin of Shape Resonance in Second-Harmonic Generation from Metallic Nanohole Arrays

Experimental data of SHG from different gold thin film samples.
(a) The measured SHG signal intensity versus the aspect ratio of the rectangular hole. The inset is a typical spectrum of the SHG signal. A resonance peak is clearly observed for the AR = 2.037 sample. (b) Convolution temporal profile of the light pulse after propagating through the AR = 2.037 and AR = 0.491 patterns, with a relative time-delay readout of 6.5 fs. The inset is the measured time delay versus aspect ratio, obtained by taking square vacant areas as references.