硫系玻璃Ge_(28)Sb_(12)Se_(60)薄膜光学非线性增强色散特性

Dispersion characteristics of optical nonlinearity enhancement of chalcogenide glass Ge_(28)Sb_(12)Se_(60) film

采用真空热蒸发以及退火工艺制备了支持局域表面等离激元的微纳结构薄膜,在此薄膜上蒸镀了硫系玻璃Ge_(28)Sb_(12)Se_(60)薄膜。应用Z-扫描技术,在飞秒激光脉冲激发下研究其光学非线性增强的色散特性,在650 nm和850 nm波段观察到了非线性吸收增强;非线性折射率随着波长的增加由负变正。通过扫描电子显微镜和透过光谱表征和分析了硫系玻璃Ge_(28)Sb_(12)Se_(60)薄膜非线性吸收增强的原理,非线性吸收随着波长的增加由单光子吸收为主逐渐转变为双光子吸收为主;银膜的微纳结构导致硫系玻璃薄膜的共振中心频率发生了偏移。实验制备的用于增强硫系玻璃非线性的微纳结构制作简单,无需复杂光刻工艺,为非线性光子学器件的设计提供了新的思路。

Micronano structure films supporting local surface plasmons were prepared by vacuum thermal evaporation and annealing,and the chalcogenide glass Ge_(28)Sb_(12)Se_(60) film was evaporated on this film.The dispersion characteristics of optical nonlinear enhancement were studied by the Z-scan technique under femtosecond laser pulse excitation.Nonlinear absorption enhancement was observed at 650 nm and 850 nm.The nonlinear refractive index changes from negative to positive with increasing wavelength.The principle of nonlinear absorption enhancement of chalcogenide glass Ge_(28)Sb_(12)Se_(60) thin films was characterized and analysed by scanning electron microscopy and transmission spectroscopy.The nonlinear absorption gradually changed from single photon absorption to two-photon absorption with increasing wavelength.The resonance center frequency of chalcogenide glass films shifted due to the micro/nanostructures of silver films.The preparation of micro/nanostructures for enhancing the nonlinearity of chalcogenide glass is simple without a complex lithography process,which provides a new idea for the design of nonlinear photonic devices.