Application of Photoelastic Effect for Excitation Signal Detection and Optimization in Laser-Induced Pressure Propagation Method

The crucial factor for ensuring space charge measurement resolution and signal intensity with the laser-induced pressure propagation method is the exceptional excitation performance. This study proposes a new approach for detecting high-frequency pressure pulse signals using the photoelastic effect. Based on the constructed pressure pulse optical detection system, the excitation characteristics and space charge measurement signals are investigated under different electrode materials and laser parameters. The experimental findings demonstrate that the selection of the target material, optimization of laser energy and spot diameter can significantly enhance the measurement resolution and signal intensity. Further, an optimized excitation scheme for the LIPP measurement device is proposed. The optimal spatial resolution and signal intensity are achieved when utilizing graphene as the target with laser energy of 340 mJ and spot diameter of 10 mm. Furthermore, the outcomes of the space charge evolution under intense electric field confirm the efficacy of the excitation optimization approach. Ultimately, the pressure pulse properties and generation process under distinct mechanisms are elucidated by integrating the developed simulation model of laser-induced pressure pulse. This study can offer valuable insights into the design of excitation scheme and investigation of the pressure wave generation mechanism in the LIPP method.