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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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We report single-shot damage threshold as a function of pulse duration (50-900 fs) for MgF2/ZnS 800-nm omnidirectional-reflection film, interference filter, and gold film. The results indicate that the damage with ultrashort pulse is nonthermal, which is different from that with long pulse. Additionally, the ablation crater depths of 45° 相似文献
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By using the dispersion theory instead of the Fröhlich Hamiltonian, the polaron energy in a quantum dot with a parabolic confinement potential is investigated at finite temperatures. It is found that the self-trapping energy of the polaron decreases with the increasing temperature, and the temperature effect is more obvious in quantum dots with weaker confinement. 相似文献
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Simulating resonance-mediated two-photon absorption enhancement in rare-earth ions by a rectangle phase modulation 下载免费PDF全文
Improving the up-conversion luminescence efficiency of rare-earth ions via the multi-photon absorption process is crucial in several related application areas. In this work, we theoretically propose a feasible scheme to enhance the resonance-mediated two-photon absorption in Er~(3+) ions by shaping the femtosecond laser field with a rectangle phase modulation. Our theoretical results show that the resonance-mediated two-photon absorption can be decomposed into the on-resonant and near-resonant parts, and the on-resonant part mainly comes from the contribution of laser central frequency components, while the near-resonant part mainly results from the excitation of low and high laser frequency components.So, the rectangle phase modulation can induce a constructive interference between the two parts by properly designing the modulation depth and width, and finally realizes the resonance-mediated two-photon absorption enhancement. Moreover, our results also show that the enhancement efficiency of resonance-mediated two-photon absorption depends on the laser pulse width(or laser spectral bandwidth), final state transition frequency, and intermediate and final state absorption bandwidths. The enhancement efficiency modulation can be attributed to the relative weight manipulation of on-resonant and near-resonant two-photon absorption in the whole excitation process. This study presents a clear physical insight for the quantum control of resonance-mediated two-photon absorption in the rare-earth ions, and there will be an important significance for improving the up-conversion luminescence efficiency of rare-earthions. 相似文献
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High-Resolution Selective Excitation of Resonance-Enhanced Multiphoton-Ionization Photoelectron Spectroscopy by Shaping Femtosecond Laser Pulses 下载免费PDF全文
Femtosecond laser-induced resonance-enhanced multiphoton-ionization photoelectron spectroscopy (REMPI-PS) is faced with two drawbacks of low spectral resolution and poor selective excitation due to the broad spectral bandwidth. We propose a scheme to obtain a high-resolution selective excitation of (2+1) REMPI-PS by com- bining 7r and cosinusoidal phase modulation. Our theoretical results indicate that the (2+1) REMPI-PS signals related to neighboring excited states can be differentiated from their indistinguishable photoelectron spectra by the 7r phase modulation, and then their selective excitation can be realized by supplementally adding the cosi- nusoidal phase modulation. Furthermore, the physical mechanism of the high-resolution selective excitation of (2+1) REMPI-PS is explained by considering the two-photon power spectrum. 相似文献
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