摘要
采用超短脉冲近红外光(1.06μm)激发,首先在多孔硅表面观察到了较强的可见区荧光产生.荧光强度与激发光强度的三次方关系表明,有效的荧光产生起源于三阶非线性光学效应的增强.对多孔度低的样品观察不到这种荧光发射.通过与多孔硅的紫外光(355 nm)激发谱的比较,我们把这种有效的多光子激发过程归结为来源于多孔硅的量子约束效应.
We demonstrate for the first time that the porous silicon layer(PSL) which has a brightlight-emission band in the range 500--700nm, exhibits a strong visible-range luminescenceunder the illumination of infrared ultrashort-pulsed laser. The intensity dependence of integ-rated luminescence on pump power shows that this is a third-order nonlinear optical effect.By comparing with UV-light-excited spectra of PSL and samples with low porosity which haveinefficient luminescence, a possible explanation that the large nonlinear optical response is dueto the quantum-confinement effect has been proposed.
关键词
多孔硅
光子激发
荧光
Laser applications
Porous materials
Semiconductor quantum wells
Solid state lasers
