共查询到20条相似文献,搜索用时 0 毫秒
1.
R. Giovanelli 《Il Nuovo Cimento D》1995,17(1):61-83
Summary A direct numerical analysis, based on the Lienard-Wiechert potentials, is performed in the present paper, aiming to describe
the relativistic interaction of the electrons composing a high-intensity beam (in Raman regime) both with each other and with
the fields of an FEL structure and of an external resonant travelling electromagnetic wave. The different accelerations, due
to the various forces acting on the charged particles, are seen to give different contributions to the total radiation field,
which are separately considered here. The angular and frequency distributions of the obtained radiation are compared with
the analytic ones deduced in the particular case of a single charge launched along the FEL structure. The interference effect
between the fields of many bunches is seen to cause the shrinkage of the resulting radiation beam. 相似文献
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J. Feldhaus E. L. Saldin J. R. Schneider E. A. Schneidmiller M. V. Yurkov 《Optics Communications》1997,140(4-6):341-352
A new design for a single pass X-ray Self-Amplified Spontaneous Emission (SASE) FEL is proposed. The scheme consists of two undulators and an X-ray monochromator located between them. The first stage of the FEL amplifier operates in the SASE linear regime. After the exit of the first undulator the electron bunch is guided through a non-isochronous bypass and the X-ray beam enters the monochromator. The main function of the bypass is to suppress the modulation of the electron beam induced in the first undulator. This is possible because of the finite value of the natural energy spread in the beam. At the entrance to the second undulator the radiation power from the monochromator dominates significantly over the shot noise and the residual electron bunching. As a result the second stage of the FEL amplifier operates in the steady-state regime when the input signal bandwidth is small with respect to that of the FEL amplifier. Integral losses of the radiation power in the monochromator are relatively small because grazing incidence optics can be used. The proposed scheme is illustrated for the example of the 6 nm option SASE FEL at the TESLA Test Facility under construction at DESY. As shown in this paper the spectral bandwidth of such a two-stage SASE FEL (Δλ/λ 5 × 10−5) is close to the limit defined by the finite duration of the radiation pulse. The average brilliance is equal to 7 × 1024 photons/(s × mrad2 × mm2 × 0.1% bandw.) which is by two orders of magnitude higher than the value which could be reached by the conventional SASE FEL. The monochromatization of the radiation is performed at a low level of radiation power (about 500 times less than the saturation level) which allows one to use conventional X-ray optical elements (grazing incidence grating and mirrors) for the monochromator design. 相似文献
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Goro Isoyama Ryukou Kato Shigeru Kashiwagi Tetsuya Igo Yutaka Morio 《Infrared Physics & Technology》2008,51(5):371-374
Free electron laser (FEL) and self-amplified spontaneous emission (SASE) are being developed in the far-infrared region using the L-band electron linac at the Institute of Scientific and Industrial Research (ISIR), Osaka University. The L-band linac was recently remodeled extensively not only for higher operational stability and reproducibility but also for high power operation of FEL. After commissioning of the linac, we first began SASE experiment with a newly-developed strong-focusing wiggler. Recently we began FEL experiment and obtained lasing with the high peak power at 70 μm again after a long break. 相似文献
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模拟了边耦合输出用于FIR FEL 的可实用性,证明这种输出方式适合于远红外FEL。分析且模拟了光腔各种输出参数(如输出功率、腔增益、耦合效率等)随输出镜尺寸及位置的变化规律,找出了最佳的输出镜尺寸及位置。并对谐振腔有漂移管和无漂移管两种情况进行了比较。通过移动或者更换输出镜(输出反射镜),改变输出镜尺寸和位置,可以灵活地选择和调节光腔的Q值。能适应实验不同阶段的需要:例如在实验初期可以提高Q值,增大净增益;而在做饱和实验时可以增大输出,使输出功率最大。 相似文献
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Abstract A number of books, symposia, proceedings, special publications [1–9], and review papers in English covering catalytic surfaces [10, 11], solid surface characterization [12–191, thin film analysis [20–22], surface structure and bonding [23, 24], angular distribution of photoelectrons [25, 26], use of synchrotron radiation [27, 281, ion beam effects [29], different methods of surface study [30, 31], experimental and theoretical aspects of ultraviolet photoelectron spectroscopy (UPS) [32], and angle resolved UPS [33, 34] are available in literature. Reviews in other languages, namely Japanese [35–41], German [42–46], French [47–50], Italian [51], Russian [52], and Polish [53], are also available. But the present situation demands a thorough and up-to-date literature survey of the surface study by photoelectron spectroscopy in order to assess what has been done and what is left to be done. This paper is aimed at that goal. 相似文献
9.
E. S. Koteles W. H. McNeill 《International Journal of Infrared and Millimeter Waves》1981,2(2):361-371
New experimental evidence is presented which shows that, contrary to an earlier report, far-infrared surface plasmons at metal-air interfaces propagate long distances (tens of centimeters or longer). 相似文献
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The infrared and far infrared spectra of complexes formed between p-benzoquinone and phenol derivatives were studied in the crystalline state. The spectra showed the compounds to be weakly polar charge transfer complexes with hydrogen bonds. In the far infrared region hydrogen bond vibrations and internal vibrations forbidden in the free molecules were observed. 相似文献
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在Nd:YAG激光器中,用单晶硅实现了被动锁模,得到了脉冲定义为28ps左右,能量为约3μJ的锁模脉冲,并对锁模机理作了初步解释。 相似文献
12.
Jiayu Chen Zheng Liang Yongchuan Zhang Ziqiang Yang 《International Journal of Infrared and Millimeter Waves》2000,21(10):1563-1567
A novel Smith-Purcell FEL with a relativistic electron beam of middle energy and a quasi-optical resonator composed of diffraction grating and three mirror reflector is described in this paper. Coherent radiation with peak power of tens of KW at 3 mm waveband is successfully detected from an experimental facility characterized by beam energy of 400-500 KeV, pulse length of 70 ns, pulse beam current of 0.2 KA, and pulse guide magnetic field of up to 1.2 T. 相似文献
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H. Delbarre C. Przygodzki M. Tassou D. Boucher 《International Journal of Infrared and Millimeter Waves》2000,21(6):883-894
High precision index measurements (n/n 10-5) have been recently achieved on an AgGaS2 crystal using a spectral interferometry technique with a polarized white-light continuum. Up to now, these measurements are limited to the visible and near-infrared range, the most dispersive domain. We investigate the possibility to extend the technique to far infrared index measurements. We demonstrate a criterion depending only on group velocity dispersion and crystal thickness for planning future experiments. 相似文献
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Zhang Xun Chen Weibin Zhang Hongjie Liang Huanhui Luo Xizhang 《International Journal of Infrared and Millimeter Waves》2003,24(11):1955-1965
The research development and the latest results of far-infrared laser in the last few years were introduced from the following aspects: far-infrared laser, study of basic science, study of astrophysics, communication and military applications, engineering applications, study of medical biology and other applications. 相似文献
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衰减全反射模式的傅里叶变换红外光谱仪(ATR-FTIR)可以用来确定固体粉末样品的远红外光谱性质,并根据其指纹特征对未知物样品进行鉴定, 且具有快速、简便、灵敏、样品用量少等优点,已成为分析与表征染料的常用的手段。运用ATR-FTIR在真空条件下测试了汽巴蓝2B、去氧紫草素、靛蓝、靛红、硫靛红等五种染料在50~610 cm-1范围内的吸收光谱。实验结果表明这五种染料在此波段内均有明显的特征吸收峰并对其峰位进行了指认与描述。使用Gaussian09软件对硫靛红分子进行模拟计算与指纹谱指认,并根据可视化结果可以看出:硫靛红分子在50~610 cm-1范围内的特征吸收峰主要源于分子的集体振动,且其高频与低频的振动模式并不一致。模拟结果与实验结果相对符合较好,但仍然存在一定的差异:比如峰值位置的差异、吸收峰位的移动、模拟得到的新峰位等,主要是由于二者所基于的温度不同、理论计算没有考虑分子间的相互作用、ATR晶体与样品粉末的接触效果略差以及系统分辨率不够等因素导致的结果。 相似文献
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Abstract The infrared spectrum of acetonitrile vapour has been obtained in the range below 100 cm?1. There is an absorption band located at 78 cm?1 which is assigned to overlapping intermolecular vibrations of dimer molecules in equilibrium with the monomer species. The equilibrium constant calculated from the pressure dependence of the band intensity amounts to 42 ± 26 1·mol?1. 相似文献
17.
用传统熔融淬冷法制备了一系列(100-x)(GeTe4.3)-xAgI (x=5,10,20,30)硫卤玻璃.并通过阿基米德法、XRD衍射、差热分析、可见/近红外吸收光谱、红外透射光谱等手段研究了该硫卤玻璃的热稳定性和光学特性.研究表明随着AgI含量的增加,玻璃的密度从5.591 g·cm-3递增到6.314 g·cm-3|折射率从3.73上升到5.70|XRD衍射数据表明该玻璃体系在较宽的组分范围内没有微晶析出,说明成玻范围较宽|差热分析表明当x=5时玻璃有着最高的转变温度206 ℃|AgI含量增多时短波截止限发生红移,红外截止波长基本不变(均超过25 μm),表明此硫卤玻璃材料在远红外领域有很大的潜在应用前景. 相似文献
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The investigation of the physico-chemical properties of photographic sensitizers involves “inter alia” the knowledge of their vibrational spectra.1,2 Molecules such as carbocyanine dyes have these spectra tremendously complicated and the best approach to the problem has been the study of simplified model compounds with polymethine chains.3 As to the possible modification of the spectral pattern, when the adsorbed dye-silver halide complex is present, it may be presumed that much more information can be obtained from the far infrared region, where chain motions and lattice external modes are absorbing. 相似文献
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用传统的熔融淬冷法制备了远红外Te基硫系玻璃(Ge15Ga10Te75)100-x(KBr)x(x=2、4、6、8mol%).利用X射线衍射仪、差示扫描量热仪等设备测试玻璃的结构和物化性质,分析了引入KBr对Te玻璃的结构、化学和物理热稳定性等方面的影响;利用分光光度计、红外光谱仪等光学方法研究了该类Te玻璃的光谱性质,分析了KBr对该类玻璃的短波吸收和红外透过光谱的影响;利用Tauc方程估算了玻璃样品直接和间接的光学带隙.实验结果表明:随着KBr含量的增加,玻璃的短波截止边发生红移,而红外截止边基本没有发生变化,该组玻璃始终保持较宽的红外透过范围. 相似文献
20.
Alessandro Bertolini Giorgio Carelli Augusto Moretti Giovanni Moruzzi 《International Journal of Infrared and Millimeter Waves》2001,22(12):1761-1768
Metal-Insulator-Metal (MIM) and Schottky-barrier diodes have been used extensively in the past years as harmonic generators and mixers for frequency measurements in the spectral range from the far-infrared to the visible. MIM diodes present a very low fabrication cost and are easy to handle, while Schottky diodes are mechanically more stable and long-lived. In the present work we discuss the performance of a metal-semiconductor point-contact diode for the radiation around 1 m. This device, which may be viewed as a hybrid between a MIM and a Schottky diode, combines the simplicity and easiness of fabrication of the MIM diode with the stability and the long contact life typical of the Schottky diode. It proved to be very efficient even for visible light. 相似文献