Energy Evaluation of Shock Wave Emission and Bubble Generation by Laser Focusing in Liquid Nitrogen.

Abstract

When the energy level of a laser beam at the focus exceeds an irradiance threshold the optical breakdown occurs, followed by a series of high-speed phenomena such as plasma formation, shock wave emission and vapor bubble generation. In this paper the energy evaluation associated with these phenomena has been made for laser focusing in liquid nitrogen. It is found that the threshold laser energy capable of bubble formation has an extent with some probability, tending to decrease with increasing the applied pressure. The mechanical energies of shock wave emission and bubble generation have been investigated.