The influence of quantum confinement on third-order nonlinearities in porous silicon thin films

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Colleges, School and Institutes


We present an experimental investigation into the third-order nonlinearity of conventional crystalline (c-Si) and porous (p-Si) silicon with Z-scan technique at 800-nm and 2.4-μm wavelengths. The Gaussian decomposition method is applied to extract the nonlinear refractive index, n2, and the two-photon absorption (TPA) coefficient, β, from the experimental results. The nonlinear refractive index obtained for c-Si is 7 ± 2 × 10-6 cm2/GW and for p-Si is -9 ± 3 × 10-5 cm2/GW. The TPA coefficient was found to be 2.9 ± 0.9 cm/GW and 1.0 ± 0.3 cm/GW for c-Si and p-Si, respectively. We show an enhancement of the nonlinear refraction and a suppression of TPA in p-Si in comparison to c-Si, and the enhancement gets stronger as the wavelength increases.


Original languageEnglish
Article number1810
Pages (from-to)1810
Number of pages9
JournalApplied Sciences (Switzerland)
Issue number10
Publication statusPublished - 3 Oct 2018


  • silicon, nonlinear nanophotonics, third-order nonlinearity, self-focusing, TPA, porous silicon, Z-scan