Impact of pre-pulse current and delay time on 46.9 nm laser with larger inner diameter alumina capillary  

作　　者：Muhammad Usman Khan Yongpeng Zhao Dongdi Zhao Huaiyu Cui Ziyue Cao Bo An Feifei Zhang Muhammad Usman Khan;赵永蓬;赵东迪;崔怀愈;曹子悦;安博;张飞飞(National Key Laboratory of Tunable Laser Technology,Institute of Optoelectronics,Department of Electronics Science and Technology,Harbin Institute of Technology,Harbin 150080,China)

机构地区：[1]National Key Laboratory of Tunable Laser Technology,Institute of Optoelectronics,Department of Electronics Science and Technology,Harbin Institute of Technology,Harbin 150080,China

出　　处：《Chinese Optics Letters》2020年第11期50-57,共8页中国光学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos. 61275139 and61875045)。

摘　　要：In this Letter, we firstly, to the best of our knowledge, demonstrated the influence of pre-pulse current and delay time on the intensity of a discharge pumped Ne-like Ar soft X-ray laser operating at 46.9 nm by employing an alumina capillary having an inner diameter of 4.8 mm. Specifically, the delay time was changed from 8 to 520 μs in small intervals. The pre-discharge current was increased from 25 A to 250 A through small steps, while keeping the main discharge current constant. Usually, a small pre-discharge current is applied to an Ar-filled capillary to attain a plasma column having sufficient pre-ionization before the injection of the main current. The predischarge current of 140 A was declared the best current to obtain lasing with a 4.8 mm diameter capillary.The laser spots were captured at best time delays for the pre-discharge currents of 25, 45, 80, 140, and250 A, which support the experimental results. We observed that by applying the pre-discharge current of140 A, the laser spot exhibits small divergence, higher symmetry, and uniformity, which is clear evidence of strong amplification. The laser spot obtained at 140 A is cylindrically symmetric and has a better structure than those reported by all other groups in the literature. Hence, the laser spot indicates that the laser beam is highly focusable and beneficial for the applications of the 46.9 nm laser. Results of this Letter might open a new way to enhance applications of a 46.9 nm capillary discharge soft X-ray laser.

关 键 词：Z-PINCH pre-discharge kink instabilities beam divergence 

分 类 号：TN248[电子电信—物理电子学]