Observation of gain coefficients of 15.47 nm Li-like Al soft x-ray laser in a recombining plasma pumped by a compact YAG laser

摘要

A Li-like Al soft x-ray laser oscillation (15.47 nm) by means of recombination plasma scheme was investigated to enhance the gain coefficent of lasing medium. In this study, we employed a Nd:YAG laser pulse composed of 8-pulse train, in which each pulse width was 400 ps and its interpulse time was 400 ps. The laser beam was tightly line-focused into 50 mu m in height and 12 mm in length on Al slab target by using prism lens array. The created cylindrical plasma showed that with increasing plasma length the lasing intensity at 15.47 nm increased expoentially up to 3.5 mm. For the laser energy of 3 J, the gain coefficient was 8.3 cm(-1). Above 3.5 mm in length, the signals seemed to increase linearly, indicating that the lasing action reached the saturation regime.