文献类型：期刊文献

英文题名：Method for efficient excitation of selective vibration modes in pulsed laser photothermal actuation

作者：Li, J.[1];Liao, X.[1];Meng, Z.[1];Jiang, Y.[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai, Peoples R China

年份：2023

卷号：133

期号：11

外文期刊名：JOURNAL OF APPLIED PHYSICS

收录：;EI(收录号：20231213761578);WOS:【SCI-EXPANDED(收录号:WOS:000952215300013)】；

基金：ACKNOWLEDGMENTSThis work was supported by the National Natural Science Foundation of China (Grant No. 52075172).

语种：英文

外文关键词：Irradiation - Laser excitation - Nondestructive examination - Resonators

摘要：Photothermal excitation based on thermoelastic mechanisms is widely used in non-destructive testing, precision operations, and driving micro-resonators. The narrow drive bandwidth of the high vibration mode in photothermal excitation limits its application to multi-mode drives. Controlling the laser's irradiation position is an effective solution. In this study, we build a theoretical model to achieve selective and efficient excitation of different flexural vibration modes of beams with different supports. The model can be extended to other thermal and physical boundaries, which is validated by numerical simulations and experimental results. The results show that higher modes with complex periodic shapes can be efficiently excited by focusing the laser at the peak of the absolute value of the second derivative of the flexural mode while focusing the laser at the inflection point of the mode shape will result in extremely small amplitudes. Our study indicates that the thermal gradient plays a vital role in the oscillation of the beam. The conventional view assumes that the resonance of the photo-thermal excitation beam is caused by the local expansion and contraction of the material, which cannot completely explain the dependence principle of the photothermal vibration on the laser irradiation position. To investigate the mechanism of beam resonance under laser excitation, three excitation modes, unidirectional excitation, bidirectional in-phase excitation, and bidirectional anti-phase excitation, were established, and the conversion process of optical energy to mechanical energy under laser excitation was analyzed. These results provide new options for optimal excitation and multi-mode energy flow control in photothermal driving.