Enhancement of two-photon absorption in anisotropic mesoporous silicon

✍ Scribed by V.Ya. Gayvoronsky; M.A. Kopylovsky; Yu.V. Gromov; S.V. Zabotnov; N.A. Piskunov; L.A. Golovan; V.Yu. Timoshenko; P.K. Kashkarov; G.Y. Fang; C.F. Li

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 100 KB
• Volume: 5
• Category: Article
• ISSN: 1612-2011
• DOI: 10.1002/lapl.200810080

✦ Synopsis

In experiments on nonlinear-optical transmission of picosecond laser pulses at the wavelength of 1.064 μm threeorder-of-magnitude enhancement of the photoinduced absorption in optically anisotropic mesoporous silicon films compared to crystalline silicon (c-Si) was found. The effect is not sensitive to the polarization of the laser radiation and it saturates at laser peak intensities about 5 MW/cm 2 . Higher laser intensity results in the polarization-sensitive photoinduced absorption, which is merely one-order-of-magnitude more effective than in c-Si. These efficient nonlinear-optical responses can be attributed to the resonant excitation of the defect states in the direct gap of silicon and local-field enhancement in the mesoporous films. Laser intensity, MW/cm 2 Total transmittance, % 70 68 66 64 15 10 5 0 E ⊥ [001] E ||