Reflection and Diffraction of Laser Plasma Induced by Bombardment of TEA CO2Laser at Low Pressures

A transversely excited atmospheric-pressure (TEA) CO2laser beam has been focused on a Zn plate at reduced ambient gas pressure. It is demonstrated that reflection and diffraction phenomena take place in the laser plasma when the free expansion of the laser plasma is limited by an obstructing material placed in front of the target. These findings strongly support the shock wave model for explaining the mechanism in forming a laser plasma.