Nanosecond pressure pulse profile visualization based on the density dependence of the critical angle of total internal reflection

New method is presented to observe the nanosecond pressure pulse field developed by the pulse laser energy deposition into the water. The present method is based on the pressure dependence of the refractive index of water, and the change in pressure can be visualized by the change in the reflectivity of the optical prism-water interface. Two procedures are tested to record the pulse laser induced high-pressure shock wave front in water, that is, (1) monitoring the time evolution of the laser intensity by a photomultiplier reflected from a point on the interface, and (2) taking an instantaneous photograph of the interface. They will give the pressure-time profile by the procedure, and to give the pressure distribution at that instant. Experimental results shows the feasibility of the method.