Observation and application of laser induced shock wave

A high pressure pulse is produced from optical fiber output surface by pulse laser. We found that enhancement of absorption of laser energy takes place at the output surface, if the surface is intentionally roughened. The effect causes the pressure enhancement of the generated shock wave in water. We also found high pressure shock propagation in water from the fiber that output surface was roughened and rounded intentionally. It gives further strengthening of the shock wave generation. These phenomena can be used as a controllable pressure pulse source for microsurgery in medicine. The phenomena have been observed by the pulse laser shadowgraphy. The shock wave propagation characteristics are found to depend upon various parameters such as the fiber diameter, the fiber material, the surface roughness, the surrounding medium, the laser energy, etc. As an example of its application, the experiment to cut gelatin by the shock wave was made. The cross section of gelatin is intensively dependent on pulse duration time width of laser. Also, application as a source for acousto-optic modulator and its advantage are mentioned.