Figure 4

Theoretical results of SHG signals as a function of the air-hole aspect ratio.

Panels (a)–(d) show the contribution from various physical factors to SHG: (a) The amplitude of FW mode ; (b) the spatial overlap factor ; (c) the FW-SHW phase mismatch factor; and (d) the SHW attenuation factor. Panels (e) and (f) display the calculated amplitude of SHW mode and SHG intensity (linear scale, with the corresponding semi-log scale plot depicted in the inset), respectively, which show a prominent resonant peak at AR = 2.3 and a three orders of magnitude variation of the SHG intensity for different AR samples with a total area of S = 260 nm × 130 nm.