高通量脉冲三倍频激光参数精密诊断

Precision Diagnosis of Third-Harmonic Laser Parameters of High-Flux Pulse

利用神光Ⅱ升级装置的三倍频激光参数精密诊断系统,对类美国国家点火装置(NIF)的激光驱动器在高通量状态下的空间、时间及能量等三倍频激光参数进行了测量,并通过提高近场分辨率,对在终端光学系统石英元件加工过程中引入的相位型周期结构进行了确认。对高通量状态下终端光学系统的远场聚焦能力和近场传输调制特性进行了研究。结果表明,相位型周期结构是引起三倍频近场调制增强的重要原因之一。

The third-harmonic laser parameters of a laser driver similar to U.S. National Ignition Facility （NIF） in a high laser-flux state, such as space, time and energy, are measured by using the third-harmonic precision diagnostic system of Shenguang II （SGII） upgraded facility. The phase-type periodic structure introduced in the machining process of the quartz components of the terminal optical system is confirmed by improving the near-field resolution. The far-field focusing ability and the near-field transmission modulation characteristics of the terminal optical system in a high laser-flux state are studied. The results show that the phase-type periodic structure is an important reason which can result in an enhancement of third-harmonic near-field modulation.