Automatic acquisition of dynamic characteristics of fused silicon particle ejection induced by laser

Particle ejection is an important phenomenon in laser damage process of fused silicon exit surface, and it has been difficult to obtain the experimental observation and dynamic parameters. A time-resolved two-frame shadowgraphy system was built to acquire the dynamic characteristics of exit surface particle ejection. A particle recognition and matching algorithm based on layered Voronoi diagram and elastic potential model was developed. Combining the steps of image registration and denoising, this method can overcome the inherent shortcomings of serious background noise and mismatch of origin in two-frame shadowgraphy technology, and can achieve 100% correct detection and matching in the image of 6 μs delayed and later. Compared with manual processing, this method can simultaneously obtain the size, velocity and flight direction of particles with pixel accuracy, and the data processing time is reduced by about 20 times.