Characterization and χ^(3) measurements of thin films by third-harmonic microscopy

Abstract

Third-harmonic (TH) generation from a thin layer on a substrate is analyzed in reflection and transmission geometry taking into account interference effects of fundamental and TH waves in the film, the backward-generated TH, and the pump-beam profile. Conditions are derived for both geometries where the signal from the film dominates, which is important for TH microscopy. The analysis results are applied to retrieve from experiment nonlinear susceptibilities χ(3) of hafnia/silica mixture (Hf(x)Si(1-x)O₂), alumina (Al₂O₃), and scandia (Sc₂O₃) thin films.

The linear and nonlinear refractive index of amorphous Al2O3 deduced from aluminosilicate optical fibers

“…Direct measurements of the nonlinear refractive index or χ (3) susceptibility of thin alumina films vary considerably in the literature . Therefore, by way of comparison, the Sellmeier fit from Ref.…”

“…35 Direct measurements of the nonlinear refractive index or χ (3) susceptibility of thin alumina films vary considerably in the literature. [36][37][38] Therefore, by way of comparison, the Sellmeier fit from Ref. 39 for thin-film Al 2 O 3 grown on a soda lime glass substrate is provided in Figure 3 (dashed curve).…”

Numerical investigation of high-order harmonic generation by gold nanorod arrays in hybrid nanostructures: effect of number of gold nanorod

“…m 2 /V 2 of HfO 2 has been used at a wavelength of 800 nm [34,35]. The refractive index of Au has been characterized based on the results [36], and the third-order susceptibility of Au in the near-infrared frequency region has been used as the value of c = ´-2.45 10 [37].…”