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《Comptes Rendus de l''Academie des Sciences Series IV Physics》2000,1(8):1053-1063
Recent progress using the VULCAN laser at the Rutherford Appleton Laboratory to pump X-ray lasing in nickel-like ions is reviewed. Double pulse pumping with ∼100 ps pulses has been shown to produce significantly greater X-ray laser output than single pulses of duration 0.1–1 ns. With double pulse pumping, the main pumping pulse interacts with a pre-formed plasma created by a pre-pulse. The efficiency of lasing increases as there is a reduced effect of refraction of the X-ray laser beam due to smaller density gradients and larger gain volumes, which enable propagation of the X-ray laser beam along the full length of the target. The record shortest wavelength saturated laser at 5.9 nm has been achieved in Ni-like dysprosium using double pulse pumping of 75 ps duration from the VULCAN laser. A variant of the double pulse pumping using a single ∼100 ps laser pulse and a superimposed short ∼1 ps pulse has been found to further increase the efficiency of lasing by reducing the effects of over-ionisation during the gain period. The record shortest wavelength saturated laser pumped by a short ∼1 ps pulse has been achieved in Ni-like samarium using the VULCAN laser operating in chirped pulse amplified (CPA) mode. Ni-like samarium lases at 7.3 nm. 相似文献
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新型X射线靶设计为:由SiO2和TiO2组成具有12个周期的一维光子晶体,在它的中间嵌入光靶材料层作为缺陷层,SiO2,TiO2和光靶层的光学厚度分别为λ4、λ4和λ2,λ为抽运激光波长.与普通平板光靶相比,当抽运光垂直照射到这种光靶时,靶层内部的光强将提高2个数量级,所以抽运激光的阈值强度将降低2个数量级,这有利于X射线激光的小型化.在同样的抽运激光照射下,X射线激光的强度将提高4个数量级,转换效率也将提高约4个数量级.由于平均电离度随抽运激光强度的提高而提高,所以采用这种光靶有利于使X射线激光向短波长推进.
关键词:
X射线激光
光子晶体
光波局域 相似文献
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本文通过分析不同泵浦功率密度下类钾硅离子X射线激光的实验结果以及有可能实现X射线激光的其它类锂离子的光谱特性,表明利用类锂离子复合方案,在现有驱动激光装置上实现“水窗”波段放大器有很大的可能性。 相似文献
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《Comptes Rendus de l''Academie des Sciences Series IV Physics》2000,1(8):999-1018
We report on the soft X-ray laser developments performed at the Institute of Laser Engineering, Osaka University especially for the collisional excitation X-ray lasers at wavelengths between 25 nm and 4 nm. The performance of neon-like and nickel-like ion X-ray lasing pumped by a train of short laser pulses has been investigated. We have also demonstrated double pass amplification using a soft X-ray multi-layer mirror at wavelengths of 19.6 nm and 7.9 nm. Based on these results and experimental technique, two targets were placed in series to double the gain length. Two opposing laser beams irradiated the double targets with a suitable time difference for quasi-traveling wave pumping. The double target amplification was successfully demonstrated with two beam irradiation for Ag, Nd, Yb, Hf and Ta lasing. The estimated absolute photon flux from the saturated amplification Ag X-ray laser was ∼300 μJ. Based on the experimental results, we also discuss the applications of an X-ray laser as a super-high brightness soft X-ray source. 相似文献
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Y. Ochi T. Kawachi N. Hasegawa A. Sasaki K. Nagashima K. Sukegawa M. Kishimoto M. Tanaka M. Nishikino M. Kado 《Applied physics. B, Lasers and optics》2004,78(7-8):961-963
We have measured temporal durations of Ni-like transient collisional excitation X-ray lasers (4d4p, J=01) using a high-speed X-ray streak camera coupled with a flat field grating spectrometer. The pumping laser pulse consisted of a 400-ps prepulse and a 4.8-ps main pulse derived from a Nd:glass laser system with chirped pulse amplification. A quasi-traveling-wave pumping using a six-step mirror was adopted to synchronize the X-ray laser pulse and the onset of gain in a plasma medium. The X-ray laser outputs from three different materials, silver (Z=47), palladium (Z=46) and molybdenum (Z=42), showed that the X-ray laser duration became shorter as the atomic number decreased. PACS 42.55.Vc; 52.50.Jm; 52.70.La 相似文献
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M. Ribière S. Sebban S. Jacquemot B. G. Chéron K. Ta?Phuoc J. Gautier J. Grunenwald P. Ribeiro M. Kozlova P. Zeitoun A. Rousse 《Applied physics. B, Lasers and optics》2012,106(4):809-816
We study pump requirements to produce femtosecond X-ray laser pulses at saturation from inner-shell transitions in the amplified spontaneous emission regime. Since laser-based betatron radiation is considered as the pumping source, we first study the impact of the driving laser power on its intensity. Then we investigate the amplification behavior of the K-α transition of nitrogen at 3.2?nm (395?eV) from radiative transfer calculations coupled with kinetics modeling of the ion population densities. We show that the saturation regime may be experimentally achieved by using PW-class laser-accelerated electron bunches. Finally, we show that this X-ray laser scheme can be extended to heavier atoms and we calculate pump requirements to reach saturation at 1.5?nm (849?eV) from the K-α transition of neon. 相似文献
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A new mechanism for pumping of an X-ray laser by an optical laser is suggested. The inverse population between the inner levels of atoms is attained by means of the use of fast laser plasma electrons. 相似文献
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Photoelectric pumping of inner shells of intermidiate Z materials is shown to be efficient for inverting the population of radiative transitions around 1 keV. Non-radiative processes are shown to be essential for achieving a stationary inversion. Reported intense X-ray bursts from plasmas generated by laser radiation suggest the use of a Nd laser as exciting source. Threshold evaluations show that a mirrorless X-ray laser is possible by use of nowadays available Nd lasers. 相似文献
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Current activities on our research of soft X-ray lasers and higher harmonic generations using intense, subpicosecond lasers are reviewed. Especially for soft X-ray lasers we experimentally demonstrate that by longitudinally pumping 2-mm-long molybdenum preformed plasma with high-intensity 475 fs duration laser pulse, a highly directive soft-X-ray laser at 18.9 nm wavelength is generated. The divergence of the beam is evaluated to be of the submilliradian order, and only requires pump laser energy of 150 mJ. Simulations show that the pedestal in the main pump pulse can generate electron density and gain profiles with large spatial gradients, which result in the selective amplification of low-order transverse modes. The present result is the demonstration of an efficient and alternative method of improving the spatial coherence of X-ray lasers with amplified spontaneous emission medium, with possibilities of becoming an excellent tool to explore various application experiments. In higher harmonic generation, topics related to observation of blue shift due to collisionless absorption process is described. 相似文献
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类Na铜离子软X射线激光初步研究 总被引:1,自引:0,他引:1
本文报道在上海光机所LF12~#激光装置上利用自制极紫外掠入射光栅摄谱仪,进行类Na铜离子复合泵浦软X射线激光研究的初步实验结果,低泵浦条件下(2.5×10~(12)W/cm~2)的光谱表明,得到自发发射放大是有希望的。文章还给出了类Na等电子数序列离子复合激光波长与原子序数的关系及推广到水窗波段的可能性。 相似文献
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A. A. Andreev A. K. Van’kov K. Yu. Platonov Yu. V. Rozhdestvenskii S. P. Chizhov V. E. Yashin 《Journal of Experimental and Theoretical Physics》2002,94(5):862-868
Theoretical estimates are given along with the first experimental results on the observation of resonance fluorescence in nuclei of rubidium isomer under conditions of laser plasma X-ray pumping of the contiguous transition with an energy of 3.4 keV. The laser plasma is prepared by irradiating a silver target by a powerful radiation of a Nd laser with a pulse duration of 600 ps. It is demonstrated how one can use the recorded number of emitted γ quanta to determine the probability of low-energy nuclear transition excited by laser plasma X rays. 相似文献
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K. Gäbel Ch. Bergmann E. Fill E. Förster I. Uschmann 《Applied physics. B, Lasers and optics》1993,56(1):3-7
Photo-resonant pumping of X-ray lasers requires close coincidence of a strong emission line with a suitable absorbing transition. We use a high-resolution crystal spectrometer to verify five coincidences, one of which has apparently not yet appeared in published work. All but one of the coincidences are found to lie within one linewidth. With respect to X-ray laser photo-pumping three of the five coincidences seem to be promising candidates. 相似文献