Origin of photoelastic phenomena in Ge-Se network glasses
Origin of photoelastic phenomena in Ge-Se network glasses
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DOI：
10.1103/physrevb.104.214209
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发表时间：
2021-12
影响因子：
3.7
通讯作者：
Lizhu Li;A. Khanolkar;J. Ari;P. Deymier;P. Lucas
中科院分区：
文献类型：
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作者：
Lizhu Li;A. Khanolkar;J. Ari;P. Deymier;P. Lucas
用激光诱导瞬态光栅法测量了一系列Ge-Se玻璃在亚带隙光照射下的弹性性质。弹性模量随辐照强度的增加而显著降低。发现在高平均配位比的玻璃中，该过程不太突出。在毫秒范围内测量的动力学被发现是太慢的光致电子过程，而不是建议的热起源。红外热成像是在照射过程中进行监测温度变化的光暗化，光膨胀，和光弹性测量。据发现，在观察到光弹性的照射条件下，所有的光结构变化都与温度的变化直接相关。COMSOL模型的热流通过样品密切再现光暗化的动力学。作为温度的函数的瞬态光栅测量证实，在照射过程中的弹性的变化基本上是一个热诱导的过程。现有的实验证据表明，光弹现象不是一个光电过程，而是激光加热的结果。
The elastic properties of a series of Ge-Se glasses are measured during irradiation with sub-band-gap light using a laser-induced transient grating method. The elastic modulus is found to decrease prominently with increasing irradiation intensity. The process is found to be less prominent in glasses of high average coordination 〈r〉. Measured kinetics in the millisecond range are found to be too slow for a photoinduced electronic process and instead suggest a thermal origin. Infrared thermography is performed during irradiation to monitor temperature changes during photodarkening, photoexpansion, and photoelastic measurements. It is found that in the conditions of irradiation where photoelasticity is observed, all photostructural changes are directly associated with a change in temperature. COMSOL modeling of thermal flow through the sample closely reproduces the kinetics of photodarkening. Transient grating measurements as a function of temperature confirm that the change in elasticity during irradiation is essentially a thermally induced process. Currently available experimental evidence indicates that the photoelastic phenomena are not an optoelectronic process but rather the result of laser heating.