摘要： It is demonstrated in this paper that the infrared-up-conversion luminescence generation from porous silicon, considered as an enhanced third-order nonlinear optical effect by the recent work, is anisotropic as the polarization vector of normally incident fundamental light is rotated. A new method has been used to determine the anisotropy parameter σ of the third-order nonlinear optical tensor χ⁽³⁾. Due to the sensitivity of σ to the crystal structure and microscopic electronic properties, the difference in σ′s between porous and crystalline silicon, particularly in their phases, demonstrates that the nanometer structure of porous silicon induces a dra-matic change of the electronic band structure, but the strongly anisotropic crystal property remains unchanged.

Abstract: It is demonstrated in this paper that the infrared-up-conversion luminescence generation from porous silicon, considered as an enhanced third-order nonlinear optical effect by the recent work, is anisotropic as the polarization vector of normally incident fundamental light is rotated. A new method has been used to determine the anisotropy parameter $\sigma$ of the third-order nonlinear optical tensor $\chi$⁽³⁾. Due to the sensitivity of $\sigma$ to the crystal structure and microscopic electronic properties, the difference in $\sigma$′s between porous and crystalline silicon, particularly in their phases, demonstrates that the nanometer structure of porous silicon induces a dra-matic change of the electronic band structure, but the strongly anisotropic crystal property remains unchanged.

中图分类号:  (Porous materials)

• 78.55.Mb

61.43.Gt (Powders, porous materials) 71.23.Cq (Amorphous semiconductors, metallic glasses, glasses) 72.80.Ng (Disordered solids)