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研究了脉冲调制红外激光激励下,碳纳米管薄膜吸光层修饰的微悬臂梁的光-热-机动态响应特性。基于有限元分析软件COMSOL5.0分析了微悬臂梁的动态温度分布,由此建立了随时间变化的一维动态温度状态方程和微悬臂梁振动方程,进而从理论上分析了微悬臂梁动态响应特性。采用波长为1550nm,以最大输出功率为10m W的激光二极管作为激励源,激光调制频率范围为0Hz至400Hz,利用振动信号拾取系统进行了微悬臂梁振动特性测试实验。实验结果表明,微悬臂梁的振幅随激光调制频率的增加而减小,微悬臂梁的最大光热响应频率约为181Hz;振幅随激光功率的增加而增加,其线性相关系数为0.993,最大偏差为±2.8m V。研究结果证明了采用该CNTs薄膜修饰的微悬臂梁作为光热偏转光谱痕量物质探测系统的热传感器件的可行性。
The dynamic response of the microcantilever micro-cantilever beam excited by pulsed-modulated infrared laser excited by carbon nanotube thin film absorber was studied. Based on the finite element analysis software COMSOL5.0, the dynamic temperature distribution of micro-cantilever was analyzed, and the one-dimensional dynamic temperature equation of state and the micro-cantilever vibration equation with time were established. Then the dynamic response of micro-cantilever was analyzed theoretically characteristic. Using a laser diode with a wavelength of 1550 nm and a maximum output power of 10 mW as the excitation source, the laser modulation frequency range is 0 Hz to 400 Hz, and the vibration characteristic of the micro-cantilever is tested by using a vibration signal pick-up system. The experimental results show that the amplitude of micro-cantilever decreases with the increase of laser modulation frequency. The maximum photothermal response frequency of micro-cantilever is about 181Hz. The amplitude increases with the increase of laser power. The linear correlation coefficient is 0.993. The maximum deviation ± 2.8mV. The results show that this CNTs thin film modified microcantilever can be used as a thermal sensing device for the detection of trace-level substances in the photothermal deflection spectroscopy.