Effects of Laser Pulse Energy on Laser Induced Bubble Behavior: Far from Boundaries Case

Abstract

To investigate cavitation bubble behavior far from boundaries, pulsed laser has been used to generate a single bubble. From high energy density of a pulsed laser, focusing it easily overcomes the optical breakdown threshold of water. The plasma is locally generated at and near the focusing point, and rapidly cools down to turn water into vapor. Varying laser pulse energy, bubble has been produced far from the boundaries, and the time-series behavior has been taken by the Schlieren imaging technique, which enables accurate boundary extraction from image processing. At 30mJ of laser pulse energy, bubble goes through the following: expansion, collapse, rebound, collapse, rebound and water jet formation, and final collapse. However, at 42.6mJ, the bubble expands, collapses then rebounds with water jet, and finally collapses.