Growth of dendrites in a large bore HyBrID copper vapor laser

Rapid growth of copper dendrites on the surface of copper metal has been observed in the discharge region of a large-bore (80 mm diameter) HyBrID copper vapor laser. The dendrites have the shape of deposit morphology. And the maximum average growth rate is around 0.25 mm/h in height and width. Also, a dendrite of 25 mm in maximum height and width appears after an operating time of 150 h. As a result, the average laser output power decreases to 75% of the initial level of the output power owing to the dendrites obstructing the laser beam.