Enhancement of two-photon absorption in anisotropic mesoporous silicon

Abstract

Abstract: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. Total transmittance of the birefringent mesoporous silicon film versus the laser intensity for the sample of 49% porosity. The crystallographic direction [001] corresponds to the optical axis

Nonlinear-Optical Properties of Porous Silicon Nanostructures

“…In I-scan measurements the light intensity is controlled in broad limits by means of optical attenuator, whereas the laser-beam cross section has no variation. [85][86][87][88]…”

Effects of laser-induced quenching and restoration of photoluminescence in hybrid Si/SiOxnanoparticles

“…At the same time, despite the more than 20 years of investigation into silicon nanoparticles, there are as of yet no satisfactory models of their structure (which, incidentally, can strongly depend on their synthesis methods and conditions) and mechanisms governing the transfer of excitation energy and subsequent electronic processes therein. For this reason, investigations into the photophysics of Si nanoparticles and also more complex Si-based nanoobjects [12][13][14][15] are being actively continued with the use of more and more sophisticated techniques, nonlinear optical ones in particular [16].…”

Impact of Water Adsorption on Nonlinear Optical Properties of Functionalized Porous Silicon

“…The covering silicon natural oxide shell is close to stoichiometric SiO 2 [19] with low concentration of the deep traps and low surface density of the silanol groups. Their efficient NLO response can be observed at lower peak laser intensities (<3 MW/cm 2 ) that is out of scope of this study [6, 20]. …”