Influence of the gain-length product on the pulse duration of highly saturated capillary discharge soft X-ray laser

Abstract

In this paper, the variation of the pulse duration was investigated for the highly saturated capillary discharge Ne-like Ar 46.9 nm soft X-ray laser. The evolutions of the pulse duration along the axis of capillary were measured for the 3.2- and 4.0-mm-inner-diameter alumina capillaries. Then, the simulations for the evolution of pulse duration were conducted with consideration of the saturation effect of laser amplification, showing good consistency with the experimental results. The analysis was performed on the variation of pulse duration over plasma length, indicating that the variation of the gain-length product caused the evolution of the pulse duration. Meanwhile, the evolutions of pulse durations were measured for different initial Ar pressures for both capillaries, showing the pulse durations were wider near the optimum pressure. Based on the simulations and the experimental results, it is concluded that the variations of the pulse duration of the soft X-ray laser were mainly due to the effect of gain-length product.