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1.
毛细管放电条件下类氖序列原子参量计算与分析 总被引:2,自引:0,他引:2
利用多组态求解相对论性的Hartree-Fock-Roothan方程(HFR)方法计算了类氖离子(Z=13~27)2s^22p^5—2s^22p^53s能级之间跃迁的原子参量,包括类氖氩激光系统的能级,振子强度,自发辐射衰变速率,能级寿命,电子碰撞激发截面及电子碰撞激发速率系数等。以类氖氩离子为例,分析了等离子体内46.9nm激光跃迁的粒子数反转的形成及谱线放大过程,讨论了其它几条谱线产生增益的可能性,分析了激光线振子强度随核电荷数的变化规律。根据获得的原子参量,计算了利用毛细管放电产生类氖氩和类氖氪x射线激光的放电参量,其中类氖氩毛细管放电的初始压强的范围为30~90Pa,放电电流峰值为10~50kA。理论计算结果为类氖氩x光激光实验分析,深入研究等离子体反转动力学,激光增益的估算及理论方案设计等提供了基本数据。 相似文献
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报道了毛细管放电69.8 nm软X射线激光的光强分布特性. 实验中所用毛细管长度为35 cm, 放电主脉冲电流幅值为11.5 kA, 放电初始气压为14-16 Pa. 测得的光斑强度分布由两部分构成, 在中心有一个占光强绝大部分的主峰, 其发散角约为0.4 mrad, 边缘还有两个小的离轴峰, 峰-峰发散角约为1.5 mrad. 理论上采用几何光学近似的方法对其光强分布进行计算, 光斑如此小的发散角主峰的出现, 可能主要是由于毛细管放电过程中电子密度在轴心处具有轻微凹陷造成的. 相似文献
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建立了计算69.8nm激光增益系数的理论模型,根据实验参数,计算了在主脉冲电流为12 kA时,69.8nm激光增益系数最大值为0.32 cm~(-1).理论模拟了不同初始气压下增益系数在毛细管径向上的分布情况.对理论结果的分析表明,最佳的初始气压在12—14 Pa范围内,此时69.8nm激光增益系数的极值最大.实验上,利用毛细管放电装置和罗兰光谱仪,测量了不同气压下的69.8nm激光强度,实验确定的最佳气压为16 Pa,与理论结果相近.此外,实验测量的增益系数(0.4 cm~(-1))略高于理论计算的增益系数(0.32 cm~(-1)). 相似文献
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Laser pulses with energy of ~10μJ are generated at 46.9 nm on the 3p - 3s transition of the Ne-like Ar by a fast capillary discharge setup in both 3- and 4-mm channels. The dependence of the laser output pulse energy on the pressure of Ar gas is measured for 3-mm-diameter capillaries at currents of 25, 30, and 35 kA. Under the same discharge conditions used in 3-mm capillaries, experiments indicate that higher and faster current pulses are required to produce soft X-ray amplification in 4-mm-diamater capillaries. 相似文献
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Capillary discharge soft X-ray laser, which is always called “table-top soft X-ray laser,” is one of the effective methods for miniaturization. The method is deemed to have experimental facility with practicable value. With capillary discharge mechanism, Ne-like Ar at 46.9 nm soft X-ray laser has been obtained, and the experimental results and the analyses are reported in this paper. Experimentally, a current pulse with the amplitude of 20 kA was used to excite three different gases: Ar, Kr, and N2. The signals were detected by an X-ray diode (XRD), and the emission spectra were monitored with a Rowland spectrograph. The J = 0–1 line and one 3d-3p transition of Ne-like Ar were detected, with wavelengths of 46.9 nm and 48.5 nm, respectively. Adjusting the pure Ar to the appropriate pressure, the authors found that the J = 0–1 line gains amplification, while 3d-3p does not. When the Ar pressure was 26 Pa, the J = 0–1 line completely dominated the spectrum. N2 and Kr were used as the materials of capillary discharge respectively. The spike signal was obtained by XRD, then the spectrum was detected by Rowland spectrograph, and the spectrum of Kr7+ was found. 相似文献
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Characteristics of a Ne-like Ar 46.9-nm soft X-ray laser in capillary discharge at a low Ar pressure
A capillary discharge-pumped Ne-like Ar 46.9-nm soft X-ray laser at a low Ar pressure (28–46 Pa) is proven. To our knowledge, this is the first time an XRD laser output in the condition of the low threshold of a main-current pulse spike (20–21 kA) is demonstrated. The Al2O3 ceramic capillary tube is 20 cm in length (Mo electrode is 4 cm in length) and 3 mm in diameter. The maximum laser energy of the precalibrated XRD is 3.5 μJ. The maximum gain coefficient g = 0.46 cm?1, the maximum gain-length product is 8.28, the beam divergence is 5.4 mrad, and the laser pulse width is 1.65 ns. In addition, the results show that the laser plasma column became difficult to Z-pinch with a increasing Ar pressure, its Z-pinching state of a higher Ar pressure fluctuates more intensely than that of a lower pressure by analyzing the scattering of the delay time between the pre-and main-current pulse. 相似文献
9.
G. Tomassetti A. Ritucci A. Reale L. Palladino L. Reale S. V. Kukhlevsky F. Flora L. Mezi J. Kaiser A. Faenov T. Pikuz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(1):73-77
A capillary discharge soft X-ray laser operating at 46.9 nm on the transition 3p-3s (J = 0-1) of the Ne-like Ar has been realized by exciting the active medium with a long half-cycle duration current pulse of
140 ns. The current is produced by discharging a 10 nF water dielectric capacitor, initially charged to voltages lower than
200 kV by a six stage Marx generator, through a 15-cm long capillary channels. The laser amplification has been obtained by
properly adjusting all the other experimental parameters. Utilizing a 3-mm in diameter Al2O3 capillary channel initially filled with 0.3 torr of Ar pressure, a laser beam, which has a 4-mrad divergence and a time duration
of 1.3 ns, is characterized by a gain of 0.6±0.1 cm-1. The stability of the plasma compression followed by the laser emission is verified.
Received 13 December 2001 相似文献
10.
Shan Jiang Yong-peng Zhao Yao Xie Miao Xu Huai-yu Cui Han Wu Yang Liu Qiang Xu Qi Wang 《Applied physics. B, Lasers and optics》2012,109(1):1-7
We demonstrated the lasing of Ne-like Ar 46.9?nm pumped by capillary discharge with the delay time between pre-pulse and main-pulse ranging from 2 to 130???s. Results show that the laser output reduced significantly when the delay time is much longer than 12???s. The temporal evolution of spontaneous radiation emitted from pre-ionized plasma implies that the observed reduction of the laser output is caused by the axial non-uniformity of pre-ionized plasma density and the decrease of pre-ionized plasma density. 相似文献
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A capillary discharge 46.9 nm Ne-like Ar laser is achieved with peak current of 20–23 kA. The variation of laser pulse duration
with initial Ar pressure and rise-time of main current is reported. Measurements show that the laser pulse durations slightly
increase with the increased pressure and increased rise-time of current. A comparison of the experimental results with the
calculation of snow-plow model indicates that the increase of laser pulse duration is the result of decreased Z-pinch velocity
at the pinch time when the radius of plasma is minimal. 相似文献
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Y. P. Zhao Y. Xie Q. Wang T. Liu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(3):379-382
With pure Ar and gaseous mixtures of Ar-He, the laser spike of Ne-like Ar 46.9 nm pumped by capillary discharge is measured
with XRD (X-ray diode) at low pressure. We observe the effects of the Ar pressure and the He ratio on the amplitude of laser
pulse. Compared with the laser spike of pure Ar, a mixture of Ar and a small quantity of He enhances the laser output. The
time of lasing onset and the duration of laser pulses are not affected by mixing He. In addition, a monochromator is used
to measure the laser pulse at 46.9 nm. This is the first observation of laser output with a Ar-He mixture. 相似文献
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Moreno CH Marconi MC Kanizay K Rocca JJ Uspenskii YA Vinogradov AV Pershin YA 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(1):911-917
We have used a tabletop soft-x-ray laser and a wave-front division interferometer to probe the plasma of a pinch discharge. A very compact capillary discharge-pumped Ne-like Ar laser emitting at 46.9 nm was combined with a wave division interferometer based on Lloyd's mirror and Sc-Si multilayer-coated optics to map the electron density in the cathode region of the discharge. This demonstration of the use of tabletop soft-x-ray laser in plasma interferometry could lead to the widespread use of these lasers in the diagnostics of dense plasmas. 相似文献
15.
Luther BM Wang Y Marconi MC Chilla JL Larotonda MA Rocca JJ 《Physical review letters》2004,92(23):235002
We have demonstrated the guiding of laser pulses with peak intensities up to 2.2 x 10(17) W/cm(2) in a 5.5 cm long plasma column containing highly charged Ar ions generated by a fast capillary discharge. A rapid discharge-driven hydrodynamic compression guides progressively lower order modes through a plasma with increasing density and degree of ionization, until the guide collapses on axis. The lowest order mode (FWHM approximately 50 microm) is guided with 75% transmission efficiency shortly before the plasma reaches the conditions for lasing in Ne-like Ar. The subsequent rapid plasma expansion forms a significantly leakier and more absorbent guide. 相似文献
16.
Generation of millijoule-level soft-x-ray laser pulses at a 4-Hz repetition rate in a highly saturated tabletop capillary discharge amplifier 总被引:17,自引:0,他引:17
Laser pulses with energies of as much as 1 mJ were generated at a wavelength of 46.9 nm by single-pass amplification in a 34.5 cm-long Ne-like Ar capillary discharge plasma. The large gain-length product of this plasma column allows for soft-x-ray amplification in a highly saturated regime, resulting in efficient energy extraction. Average laser output pulse energy of 0.88 mJ and peak power of 0.6 MW were obtained at a repetition rate of 4 Hz. With an estimated peak spectral brightness of approximately 1x10(23)photons /(s mm(2)mrad> (2)0.01% bandwidth) this tabletop laser is one of the brightest soft-x-ray sources to date. 相似文献
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Janulewicz KA Schnürer M Tümmler J Priebe G Risse E Nickles PV Greenberg B Levin M Pukhov A Mandelbaum P Zigler A 《Optics letters》2005,30(12):1572-1574
Investigations of plasma produced by a boron nitride capillary discharge irradiated with a guided 20-TW Ti: sapphire laser pulse at a peak intensity of 4 x 10(18) W/cm2 are presented. The guided laser radiation in the plasma channel generated He-like ions that, subject to suitable plasma temperature, recombined into Li-like nitrogen ions. Intense radiation at a wavelength of 24.77 nm was observed, indicating possible lasing at the 3d(5/2) - 2p(3/2) transition in Li-like nitrogen. 相似文献
18.
Ne-like Ar 46.9 nm soft X-ray laser has been realized by the main current with different rise time. In this paper, the spectrum
of capillary discharge Ne-like Ar 46.9 nm soft X-ray laser has been detected using a Rowland spectrograph, a new method of
changing the rise time of the main current is also researched when the other conditions are fixed. The rise time will be changed
when altering the inductance of the main switch, which will influence the time of lasing onset and the energy of the laser
output. The time of lasing onset will be postponed and the energy of the laser will increase when the induction of the main
switch increases. The energy of the laser increase by 78.5% when the rise time is changed from 38 to 55 ns. 相似文献
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利用发射光谱法测量大气压He-Ar混合气体射频容性放电中的Ar亚稳态1s5(3s23p54s[3/2]2)粒子数密度。在不同的放电功率和气体组分下测量放电等离子体中的重要参数:气体转动温度、电子激发温度和Ar亚稳态1s5粒子数密度。结果表明:气体温度在不同放电功率及Ar气压在5103 Pa以内时变化不大,范围为300~350 K;电子激发温度随着放电功率的增加而增加,并且在Ar气压为4103 Pa时最大,在放电功率为70 W时达到0.58 eV;1s5粒子数密度随着放电功率以及电子激发温度的增加而增加,在放电功率为70 W、Ar气压为4103 Pa时达到1.53109 cm-3。 相似文献