基于泵浦探针法研究VO2薄膜多波段红外激光相变特性  

Phase Transition Characteristics of VO_2 Thin Films Irradiated by Multiband Infrared Laser Studied by Using Pump Probe Method

作　　者：刘志伟 路远 冯云松 胡杰 刘瑞煌 LIU Zhi-wei;LU Yuan;FENG Yun-song;HU Jie;LIU Rui-huang;LU Yuan(State Key Laboratory of Pulsed Power Laser Technology,Electronic Countermeasures Institute, National University of Defense Technology,Hefei 230037,China)

机构地区：[1]国防科技大学电子对抗学院脉冲功率激光技术国家重点实验室,合肥230037

出　　处：《光子学报》2018年第12期79-86,共8页Acta Photonica Sinica

基　　金：国家杰出青年科学基金(No.61405248);脉冲功率激光技术国家重点实验室主任基金(No.SKL2013ZR03)资助。

摘　　要：用泵浦探针法实验研究了红外激光辐照二氧化钒薄膜的相变特性.首先利用氧源-分子束外延法制备了薄膜厚度分别为20nm、40nm、60nm的三组VO_2单晶外延薄膜,并且以10.6μm的CO_2连续激光作为泵浦光,分别以1 064nm和3 459nm的纳秒脉冲激光作为探针光,对这三组薄膜分别进行了辐照实验.实验发现三组薄膜相变后对1 064nm探针光的透过率降低量平均值分别为5.26%、6.2%、8.92%,反射率降低量分别为3.09%、6.56%、4.93%;对3 459nm探针光透过率降低量平均值分别为28.4%、47.78%、55.13%,反射率升高量平均值分别为6.65%、17.87%、7.49%.结果表明:利用分子束外延法制备的纳米级VO_2薄膜相变前后对入射激光为镜面反射;薄膜对3 459nm探针光的相变特性比对1 064nm探针光相变特性显著;薄膜厚度的增加会降低相变前透过率,但是对相变后透过率降低更为明显;薄膜对10.6μm CO_2连续激光相变前后始终保持几乎不透.研究结果可为薄膜的应用提供参考.To investigate the phase transformation characteristics of vanadium dioxide thin film irradiated by infrared laser,the experiment was carried out based on pump probe method.First,three groups of VO 2 monocrystalline epitaxial thin films with thickness of 20 nm,40 nm and 60 nm were prepared by oxy\|molecular beam epitaxy,moreover,the CO 2 continuous laser with 10.6μm was used as the pump beam,nanosecond pulse laser with 1 064 nm and 3 459 nm wavelength were used as probe light respectively,and the three groups of films were irradiated respectively.It was found that the mean values of transmittance reduction of 1 064 nm probe laser after phase transformation of the three groups of films were 5.26%,6.2%and 8.92%,respectively,and the reflectivity reduction was 3.09%,6.56%and 4.93%,respectively;for the 3 459 nm probe laser,the mean values of transmittance reduction were 28.4%,47.78%,55.13%,and reflectance increase were 6.65%,17.87%and 7.49%respectively.The results show that the incident laser before and after the phase transformation of VO 2 thin films prepared by molecular beam epitaxy were both mirror reflected;the phase transition properties of 1 064 nm probe were not as significant as that of 3 459 nm probe;the increase of film thickness will reduce the transmittance before the phase change,while the decrease after the phase change is more obvious;before and after the phase transition,the film keeps almost opaque to CO 2 laser.The investigation will provide a reference for the application of film.

关 键 词：分子束外延 VO2薄膜 泵浦探针法 激光辐照 相变特性 

分 类 号：O434.14[机械工程—光学工程]