为了研究水与纳秒激光相互作用的现象,利用相机拍摄了经显微镜放大之后的击穿区域的图像。激光射入水中后,若激光功率超过击穿阈值,水被击穿,在传播方向上形成纺锤形状的等离子体光点,同时在纵向上出现光束分裂和多丝现象。增大入射能量,传输方向上光点变密,纵向上多丝现象更加明显。利用B-T理论模拟了一维光场经调制之后的光场分布,与实验结果吻合较好。

An experiment was set up to study the breakdown and filaments induced by nanosecond laser in details.While the laser beam was focused into the water, spindly light spots of plasma were observed, simultaneously, the laserbeam was splitted into several little filaments. With the increasing of pulse power, the light-spots become dense, and theradius of plasma beam become wide. The lengths of the spindly light-spots were calculated. The results of the lightdistribution after modulated by the ID light using the B-T theory fit well with that of the experimental results.