Study of the Damage Threshold of optical surfaces of high-power energy pulse lasers with changing coefficient of optical surface roughness

ABSTRACT This paper presents the measurement of the laser Threshold damage of an optical surface at different roughness coefficients. The study procedure is achieved through the manufacturing of two types of parallel-sided borosilicate plate (Glass Bk7, and SF13). The Laser used is ND: YAG pulsed laser and the longitudinal mode TEM00 laser pulses with pulse width τ =30ns and wave length λ=1.064μm, the laser beam is focused using F=30 mm lens. The concentrated laser beam is guided by a converging lens towards the optical surface of the parallel surface plate. Finally, we obtained a graph of roughness coefficient is drawn in relation the optical Threshold Damage of the optical surface, Before and after processing the optical surface. We were able to raise the threshold by about 15% after conducting thermal treatment of the optical surface.