The topical properties of oxidized free-standing porous silicon films excited by a cw laser have been investigated. It is found that samples oxidized at 800-950 deg C show a strongly superlinear light emission at an excitation intensity of approx 10 W/cm~2. This emission has a peak at 900-1100 nm and shows a blueshift as the oxidation temperature is increased. These samples also show a very large induced absorption, where the transmittance is found to decrease reversibly by <=99.7percent. The induced absorption increases linearly with increasing pump laser intensity. Both the superlinear emission and the large induced absorption are quenched when the samples are attached to materials with a higher thermal conductivity, suggesting that laser-induced thermal effects are responsible for these phenomena.
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机译：研究了用连续激光激发的氧化自支撑多孔硅薄膜的局部特性。发现在800-950℃氧化的样品在约10 W / cm〜2的激发强度下显示出强烈的超线性发光。此发射在900-1100 nm处有一个峰值，并随着氧化温度的升高呈现蓝移。这些样品还显示出非常大的诱导吸收，发现透射率可逆地降低了<= 99.7％。诱导的吸收随着泵浦激光强度的增加而线性增加。当样品附着到具有更高导热率的材料时，超线性发射和大的诱导吸收都被淬灭，这表明这些现象是由激光诱导的热效应引起的。
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