19.6nm波长类氖锗X光激光光源理论模拟

Theoretical designs of 19.6nm Ne-like Ge XRL source

波长19.6nm的类氖锗X光激光适合作为诊断激光等离子体界面不稳定性的光源。用经过实验检验的系列程序对预主短脉冲驱动类氖锗进行了系统的优化设计和理论分析。采用2%～3%的预脉冲强度,6～8ns的预主脉冲时间间隔,在4×1013W/cm2功率密度驱动下,波长19.6nm增益区的宽度可以超过60μm,增益区的维持时间可以达到90ps。对于16mm长的平板靶,增益系数可达11.8/cm;弯曲靶增益系数可达13.3/cm;单靶小增益长度积可达21.3,单靶就可以获得饱和增益。采用双靶对接,其小讯号增益可达38 4,可以获得深度饱和增益,能满足应用演示所需的X光激光光源。

19.6 nm Ne-like Ge X-ray laser (XRL) can be used as a source to diagnose Rayleigh-Taylor instability in laser induced plasma. Systemic optimum designs and theoretical analysis to Ne-like Ge XRL driven by pre-main short pulses were conducted by a series of codes, which had been tested by experiments. Simulation results show that, adopting driven conditions of 2%-3% pre-pulse, 6-8 ns pre-main pulse interval and 40 TW/cm2 power intensity, a gain area of 19.6 nm laser line beyond 60 μm and gain duration of 90 ps can be obtained. Furthermore, with 16 mm plane target, the gain reaches to 11.8 /cm, and if 6 mrad/cm curved target is adopted, it reaches to 13.3 /cm, and small signal gain-length product gain-length product of single target is about 21.3, which means that saturated gain can be realized by a single target. With double targets opposite coupling, gain-length product can reach 38.4, deep saturation can be obtained, and XRL source required by demonstration of application is out of question.