为了探究VO2薄膜受激光辐照的温度场分布, 以及1 064 nm激光直接辐照100 s内至相变的激光功率密度阈值, 并比较近红外和中红外波段透过率调制特性差异。首先基于COMSOL建立了薄膜受激光辐照的模型并进行了温度场仿真, 然后分别测试了薄膜正反面被不同功率密度的1 064 nm激光辐照100 s内激光透过率随时间响应特性。实验中的VO2薄膜利用分子束外延法在Al2O3基底上制备得到。仿真结果表明, 激光功率密度为25 W瘙
簚mm-2时,50 nm厚薄膜在被辐照1 ms时间内即达到相变温度。经激光辐照实验发现: 50 nm厚的VO2薄膜正反面受1 064 nm激光直接辐照100 s内至相变的功率密度阈值分别为4.1 W瘙
簚mm-2和5.39 W瘙
簚mm-2。30 nm厚VO2薄膜对1 064 nmn激光的透过率调制深度约为13%, 对3 459 nm激光透过率调制深度约62%, 说明VO2薄膜对近红外透过率调制特性不明显。

In order to explore the temperature field distribution and power density threshold of 1 064 nm laser that irradiate film and make it phase change in 100 s, and to compare the difference between the transmittance modulation characteristics in the near infrared and mid-infrared band, a model of laser irradiation was set up and the temperature field was simulated. Then, the 1 064 nm laser transmittance response characteristic with time was tested in the front and back face of VO2 film with different laser power density in 100 s separately. VO2 thin films in the experiment were prepared by molecular beam epitaxy on Al2O3 substrate. Simulation results show that the film reaches the phase-transition temperature in 1 ms with 25 W瘙
簚mm-2 laser power density. It is found that the laser power density threshold is 4.1 W瘙
簚mm-2 and 5.39 W瘙
簚mm-2 when irradiating the front and back face of the VO2 thin film with 50 nm thickness respectively. The transmittance modulation depth of 1 064 nm is approximately 13% of VO2 thin films with 30 nm thickness. However, compared with 62% for 3 459 nm laser, the transmittance modulation characteristic in near infrared is not obvious for VO2 thin films.