相干光学声子的操控以及对能量输运过程的影响  

Manipulation of Coherent Optical Phonon and Its Impact on Energy Transport Process

作　　者：王建立[1] 郭亮 徐先凡 倪中华[1] 陈云飞[1] 

机构地区：[1]东南大学机械工程学院江苏省微纳生物医疗器械重点实验室,南京211189 [2]School of Mechanical Engineering,Purdue University

出　　处：《工程热物理学报》2016年第11期2442-2446,共5页Journal of Engineering Thermophysics

基　　金：国家973计划(No.2011CB707605);国家自然科学基金资助项目(No.51476033)

摘　　要：利用脉冲整形器生成双脉冲泵浦光,通过调整双脉冲的间隔时间,在不改变泵浦光能量密度的前提下,实现了相干光学声子的增强和完全消除,进而研究了相干光学声子对半导体能量输运过程的影响。实验直接验证了光学声子在超快能量输运过程的重要作用。相干光学声子增强时测量得到的热电子冷却以及晶格加热的特征时间均减小,因此激发相干光学声子可提高超快能量输运效率。当电子与晶格处于热平衡状态时,相干光学声子增强和消除前后反射信号的下降趋势相同,因此光学声子对热量输运没有显著影响。Two successive pump pulses were generated by a pulse shaper, and the coherent optical phonons were enhanced or completely cancelled by changing the separation times of the double pump pulses when the pump fluences were maintained the same. This experiment provided a direct evidence of the importance of the optical phonons on the ultrafast energy relaxation process in semiconductors. The decay times of the hot-carrier cooling and the characteristic times of the lattice heating were found to decrease when the coherent optical phonons were enhanced, revealing that the energy transfers more etticiently by stimulating the coherent optical phonons. The reflectivity trace decayed back to the background almost at the same speed with and without the presence of the coherent optical phonons, indicating that the optical phonons have insignificant effect on the thermal transport process in the thermal equilibrium state.

关 键 词：飞秒激光 相干光学声子 脉冲整形器 超快能量输运 

分 类 号：TK124[动力工程及工程热物理—工程热物理]