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181.
182.
通过研究线状激光等离子体的轴向光谱,辨认和归类了一些高离化态钛离子的谱线,并发现钛等离子与表层氧化物离子体的相互作用导致轴向发射光谱强度变化的现象。 相似文献
183.
184.
利用块状介质进行飞秒强激光脉冲的腔外压缩 总被引:1,自引:0,他引:1
高强度飞秒激光脉冲的腔外压缩是获得高次谐波阿秒脉冲驱动源的必要手段.实验研究了超强超短飞秒激光脉冲在经过块状介质后的光谱展宽和色散补偿压缩现象.单脉冲能量0.26 mJ,脉宽50 fs的激光脉冲经透镜在空气中聚焦后再入射到块状材料上,出射脉冲光谱被展宽到接近40 nm.由于在块状材料中的自聚焦效应,出射光束质量变好并保持较小的空间啁啾.利用熔融石英棱镜对补偿带有正色散的出射脉冲,最后得到>0.1 mJ,19 fs的压缩脉冲.利用SPIDER装置测量了出射脉冲的脉宽和光谱相位.整个系统的能量效率大约为35%,压缩后的激光脉冲具有很好的空间分布和平滑的时域包络.实验结果实现了利用块状材料对飞秒激光脉冲的腔外压缩,这种方法将适用于对更高能量飞秒脉冲的压缩. 相似文献
185.
利用掠入射反射短波截止原理,成功地实现了平场光栅谱仪的无级次重叠摄谱.实验结果表明,利用该方法来消除平场光栅谱仪中短波长的高级谱对所考察波段的一级谱的影响是简便而有效的.实验获得了镁激光等离子体在4.4~5.6nm,5.9~11.8nm,7.0~14.0nm三个不同波段的近似的纯一级谱. 相似文献
186.
187.
We report on a systematic study of the laser polarization effect on a femtosecond laser filamentation in air.By changing the laser's ellipticity from linear polarization to circular polarization, the onset position of laser filament formation becomes farther from the focusing optics, the filament length is shorter, and less laser energy is deposited. The laser polarization effect on air filaments is supported by a simulation and analysis of the polarization-dependent critical power and ionization rates in air. 相似文献
188.
Real-time single-shot measurement of the femtosecond electron beam duration in laser wakefield accelerators is discussed for both experimental design and theoretical analysis that combines polarimetry and interferometry.The probe pulse polarization is rotated by the azimuthal magnetic field of the electron beam and then introduced into a Michelson-type interferometer for self-interference. The electron beam duration is obtained from the region size of the interference fringes, which is independent of the pulse width of the probe laser. Using a larger magnification system or incident angle, the measurement resolution can be less than 1 fs. 相似文献
189.
Nuclear fusion from Coulomb explosions of deuterated methane clusters subjected to ultraintense femtosecond laser pulses 下载免费PDF全文
This paper reports that Coulomb explosions taken place in the
experiment of heteronuclear deuterated methane clusters
((CD4)2) in a gas jet subjected to intense femtosecond
laser pulses (170mJ, 70fs) have led to table-top laser driven DD
nuclear fusion. The clusters produced in supersonic expansion had an
average size of about 5nm in radius and the laser intensity used
was 3×1017W/cm2.The measured maximum and average
energies of deuterons produced in the laser--cluster interaction were
60 and 13.5keV, respectively. From DD collisions of energetic
deuterons, a yield of 2.5(±0.4)×104 fusion neutrons
of 2.45MeV per shot was realized, giving rise to a neutron
production efficiency of about 1.5×105 per joule of
incident laser pulse energy. Theoretical calculations were performed
and a fairly good agreement of the calculated neutron yield with
that obtained from the present experiment was found. 相似文献
190.
An ultra-broadband Ti:sapphire regenerative amplifier based on spatially dispersed amplification is demonstrated experimentally. Departing from previous reports, a new design of the cavity gets the amplified pulse free from spatial chirp. Utilizing this new regenerative amplifier, chirped pulses with bandwidth (FWHM) of about 80 nm are obtained, and the bandwidth is limited only by that of the incident seed pulses. 相似文献