激光参数和光声材料对超声信号的影响

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中图分类号：O439文献标志码：A

Abstract： Photoinduced ultrasound is widely used in medical diagnosis， material characterization， nondestructive testing， structural health monitoring and other fields. These applications have specific requirements on ultrasonic intensity and bandwidth. This paper quantitatively analyzed the effects of photoacoustic materials and laser parameters on ultrasonic frequency and intensity. The following conclusions are drawn by relevant experiments. With the increase of the incident laser energy，the amplitude corresponding to all frequencies in the ultrasonic spectrum increases，and the incident laser energy is proportional to the amplitude of the ultrasound. Meanwhihle， the ultrasonic intensity increases by 15% with increase of 50mJ laser energy. The change of incident laser frequency has no effect on ultrasonic signal. The increase of gold nanoparticle concentration can not only enhance the amplitude of ultrasound，but also increase the frequency of ultrasound. The thin layer of gold nanoparticles and polydimethylsiloxane leads to insufficient absorption of light energy，and the thick layer causes the attenuation of the high frequency component of ultrasound. The mixture of carbon black and polydimethylsiloxane produces higher intensity ultrasound than the mixture of gold nanoparticles and polydimethylsiloxane under the same circumstances， but the frequency distribution is concentrated in the low frequency domain.

Keywords：photoinduced ultrasound;photoacousticmaterials； laserparameters; gold nanoparticles;carbonblack

引言

主动超声检测技术是医学诊断、材料表征、无损检测和结构健康监测的有力工具[1-12]。（剩余14758字）