|
When a high-power laser beam is incident on water, the rapid heat transfer process triggers ionization of the water in the
active region, resulting in an explosion as well as outward propagating shock waves. Here, the formation, propagation, and
interaction of underwater shock waves induced by nanosecond laser pulses were experimentally investigated. By fitting
the theoretical model (Sedov-Taylor expansion model) to the experimental results, we quantified the effective energy
carried by the shock wave during propagation. Numerical simulations with an analytic model using the distance between
adjacent breakdown locations as input obtain the shock wave emission images at different time delays and provide insights
into experimentally not accessible shock wave parameters. An empirical model is used to describe the pressure behind the
shock wave. The results show the near-acoustic propagation behavior of the shock waves at longer time delays. On top of
that, we compared the effect of the distance between adjacent excitation positions on the shock wave emission process.
The shock wave parameters in the far field are more accurate and easier to perform. Furthermore, utilizing multipoint
excitation offers a flexible approach to delve deeper into the physical mechanisms that cause optical tissue damage in
nanosecond laser surgery, leading to a better comprehension of the subject.
|
