High-speed photographic study on plasma induced by focusing IR laser

The aim of this paper is to diagnose the formation and the effect of plasma induced by focusing a Q- switched Nd:YAG laser. The laser was focused by two methods that are single lens and two lenses. The optical breakdown and the plasma formation were visualized using CCD camera in conjunction with the high-speed photography system. Sensitive paper was employed as target material. Single pulse laser was exposed on the target and the damage was examined by metallurgical method. The results obtained indicated that the size of plasma slightly increases with the laser energy. The configuration of the plasma was found in an ellipse shape and produced an irregular pattern of damage with a single lens technique. On the other hand an oval shape of plasma was appeared and symmetrical circular pattern of damage was generated with the two lenses system.