Third-order nonlinear refraction in porous silicon: Theory versus experiment
| Autor: | Domenico Ninno, P. Maddalena, Stefano Lettieri, O. Fiore, A. Morra |
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| Přispěvatelé: | Lettieri, S, Fiore, O, Maddalena, Pasqualino, Morra, A, Ninno, Domenico |
| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Philosophical Magazine B. 80:587-597 |
| ISSN: | 1463-6417 1364-2812 |
| Popis: | A z-scan measurement of the nonlinear refractive index of porous silicon (PS) is performed at a photon energy well below the effective bandgap of the sample. The measure gives ReX (3) ≈−10−8 esu, that is four orders of magnitude larger than the bulk value. We also present a calculation of the enhancement of X (3) in PS due to the spatial auantum confinement of the exciton in the quasi-one-dimensional nanostructure. The calculated enhancement is in very good agreement with the experimental data. Finally, we performed a perturbative calculation of nonlinear absorption δα in a auantum wire, obtaining the material-independent dispersive scaling of the quantum wire nonlinear refractive index. The calculation suggests the presence of a ‘auantum-confinement-enhanced’ auadratic Stark effect in the quasi-one-dimensional structure that gives a Iow and almost constant value of Reχ (3) at photon energy around half-bandgap and large negative values in the range Egap/2 < hw < Egap . As we discuss, this predict... |
| Databáze: | OpenAIRE |
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