Impact of Pre-pulse Current and Delay time on 46.9 nm Laser with Larger inner Diameter Alumina Capillary [Early Posting]
In this paper, we firstly demonstrated the influence of prepulse current and delay time on the intensity of a discharge pumped Ne-like Ar soft X-ray laser operating at 46.9nm laser with 4.8mm by employing alumina capillary having an inner diameter of 4.8mm. Specifically, the delay time was changed from 8 to 520µs in small intervals. The predischarge current was increased from 25A to 250A through small steps while keeping the main discharge current constant. Usually, a small predischarge current is applied to Ar-filled capillary to attain a plasma column having sufficient preionization before the injection of the main current. The predischarge current of 140A was declared as the best current to obtain lasing with 4.8mm diameter capillary. The laser spots were captured at best time delays for the predischarge currents of 25, 45, 80, 140 and 250A which support the experimental results. We observed that by applying the predischarge current of 140A, the laser spot exhibits small divergence, higher symmetry, and uniformity, which is clear evidence of strong amplification. The laser spot obtained at 140A is cylindrically symmetric and have well 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 46.9nm laser application. Results of this paper might open a new way to enhance applications of 46.9nm capillary discharge soft X-ray laser.
作者单位：Harbin Institute of Technology School of Astronautics
Harbin Institute of Technology
Khan Muhammad ,Khan Muhammad Usman,Zhao Yongpeng,Zhao Dongdi , Cui Huaiyu ,Cao Ziyue ,An Bo,Zhang Fefei. Impact of Pre-pulse Current and Delay time on 46.9 nm Laser with Larger inner Diameter Alumina Capillary[J].Chinese Optics Letters,2020,18(11):11.