Nath Arpita, Khare Alika
Laser and Photonics Laboratory, Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India.
Appl Opt. 2011 Jul 1;50(19):3275-81. doi: 10.1364/AO.50.003275.
The spatial and temporal evolution of laser-induced shock waves at a titanium-water interface was analyzed using a beam deflection setup. The focusing conditions of the source laser were varied, and its effect onto the dynamics of shock waves was elucidated. For a tightly focused condition, the speed of the shock wave was ~6.4 Km/s, whereas for a defocused condition the velocities reduced to <3 km/s at the vicinity of the titanium-water interface. When the laser is focused a few millimeters above the target, i.e., within the water, the emission of dual shock waves was observed toward the rear side of the focal volume. These shock waves originate from the titanium-water interface as well as from the pure water breakdown region, respectively. The shock wave pressure is estimated from the shock wave velocity using the Newton's second law across a shock wave discontinuity. The shock wave pressure for a tightly focused condition was 18 GPa, whereas under a defocused condition the pressure experienced was ≤1 GPa in the proximity of target.
使用光束偏转装置分析了钛 - 水界面处激光诱导冲击波的时空演化。改变源激光的聚焦条件，并阐明其对冲击波动力学的影响。在紧密聚焦条件下，冲击波速度约为6.4千米/秒，而在散焦条件下，在钛 - 水界面附近速度降至<3千米/秒。当激光聚焦在目标上方几毫米处，即在水中时，观察到向焦区后侧发射双冲击波。这些冲击波分别源自钛 - 水界面以及纯水击穿区域。利用牛顿第二定律，通过冲击波不连续处的冲击波速度估算冲击波压力。紧密聚焦条件下的冲击波压力为18吉帕，而在散焦条件下，目标附近的压力≤1吉帕。
