Energy-dependent losses of high-power laser radiation in liquid nitrogen.

We observed energy-dependent losses in the transmission of high-power CO(2) and HF laser radiation in liquid nitrogen resulting from scattering on small gas bubbles. The formation of these bubbles can be explained by a mechanism involving absorption of a small part of the laser radiation by microscopic suspended ice particles that leads to the evaporation of the surrounding cryogenic liquid. Even for a low concentration of these particles, the losses are significant.