超短脉冲激光空间调制下小尺度自聚焦的实验研究

实验研究了超短脉冲激光的空间小尺度自聚焦的动态变化过程.具体实验过程是使经过正交细丝的衍射来实现激光的空间调制，然后通过非线性Kerr介质二硫化碳,随着输入功率的增大,超短脉冲开始出现小尺度自聚焦增长现象.实验发现，每个小尺度自聚焦峰值并不是随着功率的增大而无限地增长下去，而是在不同位置出现了新的调制增长点，这些新出现的增长与原有的增长相互竞争，最终导致了分裂成丝.通过数值模拟相应的传输过程，发现数值模拟结果与实验结果符合很好. 关键词： 小尺度自聚焦 高功率激光 超短脉冲

Experimental research of small-scale self-focusing of ultrashort pulse with spatial modulation

The dynamic process of the small-scale self-focusing of ultrashort laser pulse is experimentally investigated. By using tabletop femtosecond laser, the pulse which is spatially modulated by the crossed-fiber diffraction passes through the carbon bisulfide. With different input power, the small-scale self-focusing of the pulse was obtained. By analyzing the contrast of the beam, we find that the small-scale self-focusing does not increase all along with the increasing of input power, but some new growth points appear in different places. They compete with each other, and finally lead to multiple splitting. The experimental results confirmed the numerical simulation.