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991.
设计了中心波长800 nm带宽约500 nm的啁啾镜对, 在550–1050 nm波长范围内提供约-60 fs2群延迟色散(group delay dispersion, GDD), 通过啁啾镜对的形式使GDD振荡波纹由单个啁啾镜的±100 fs2减小到±20 fs2. 采用双射频离子束溅射方法进行制备, 用白光干涉仪进行色散性能测试, 从测试结果可以看出, 制备的啁啾镜的反射率、GDD性能和设计值符合得比较好. 制备出的550–1050 nm超宽带啁啾镜对在钛宝石激光器腔外进行色散补偿, 原输入脉冲由24–27 fs压缩到12 fs, 这是国产超宽带啁啾镜对的首次应用.
关键词:
超快激光
啁啾镜对
群延迟色散
色散补偿 相似文献
992.
993.
S.-W. Xu Y.-X. Xie X.-D. Wang Z.-K. Li B. Guo C.-G. Leng C.-F. Wang Y. Yu 《The European Physical Journal A - Hadrons and Nuclei》2001,11(3):277-278
The very neutron-deficient isotope 133Sm was produced by irradiation of an enriched target of 96Ru with 40Ca and studied by using a helium-jet fast tape transport system in combination with X-γ and γ-γ coincidence measurements.
A simple ( EC + β+) decay scheme of 133Sm was proposed for the first time. As a by-product 133Pr was produced simultaneously because of the 98-102Ru content of the ruthenium target. The half-life of a 11/2- low-lying isomeric state in 133Pr was measured to be 1.1±0.2 s.
Received: 22 March 2001 / Accepted: 18 July 2001 相似文献
994.
995.
996.
Simultaneous forward and backward stimulated Raman scattering (SRS) in methane pumped by a single longitudinal mode Nd:YAG
laser at 355 nm has been investigated both experimentally and numerically. For forward SRS, a maximum energy-conversion efficiency
of 55% was obtained under 24 atm, while for backward SRS the corresponding figure was 58% under 4.7 atm. Under low pressures
or at low pump energies, the conversion efficiency for backward SRS was found to be much higher than that for forward SRS,
while the situation is quite the contrary under high pressures and at high pump energies. A quasi-two-dimensional numerical
model is introduced to elucidate the competition between forward and backward SRS; we conclude that the high-pressure and
high-pump-energy experimental results should be caused by the thermal defocusing effect in the SRS process. This is confirmed
by the experimental fact that a decrease of the pulse-repetition rate increases the conversion efficiency for backward SRS
but decreases that for forward SRS under high pressures. Our calculated results are in good agreement with the experimental
results at a pulse-repetition rate of 2 Hz.
PACS 42.55.Ye; 42.65.Dr; 42.65.Es 相似文献
997.
Xiaowei Chen Yuxin Leng Jun Liu Yi Zhu Ruxin Li Zhizhan Xu 《Optics Communications》2006,259(1):331-335
We experimentally demonstrate that high-power femtosecond pulses can be compressed during the nonlinear propagation in the normally dispersive solid bulk medium. The self-compression behavior was detailedly investigated under a variety of experimental conditions, and the temporal and spectral characteristics of resulted pulses were found to be significantly affected by the input pulse intensity, with higher intensity corresponding to shorter compressed pulses. By passing through a piece of BK7 glass, a self-compression from 50 to 20 fs was achieved, with a compression factor of about 2.5. However, the output pulse was observed to be split into two peaks when the input intensity is high enough to generate supercontinuum and conical emission. 相似文献
998.
999.
1000.
Xu Shuwei Li Zhankui Xie Yuanxiang Xu Furong Wang Xudong Guo Bin Leng Changgeng Yu Yong Wang Chunfang Xing Jianping Chen Hongyan 《中国科学G辑(英文版)》2003,46(2):178-184
New β-delayed proton precursor142Ho was produced via heavy ion induced reaction106Cd(40Ca, p3n), and identified for the first time by using a He-jet fast tape transport system in combination with “p-γ” coincidence
measurements. The β-delayed proton decay of142Ho was observed and its half life was determined to be (0.4±0.1) s. By fitting the experimental relative branching ratios
to final states in the proton daughter nucleus141Tb and the energy spectrum of β-delayed protons with a statistical model calculation, the ground-state spin of142Ho was assigned as 5, 6 or 7. Nuclear energy-potential-surface (EPS) calculations were performed using the Woods-Saxon Strutinsky
method. The calculated results favored the assignments of 7− to142Ho. As the by-products, some γ-transitions in the proton daughter nuclei following the β-delayed proton decays of precursors139Gd,140Tb,142Tb, and143Dy were reported here for the first time. 相似文献