自由电子激光器交叉通道腔的硬量子振荡

提出并讨论了自由电子激光器交叉通道腔内大功率可调谐硬辐射振荡的新方法。γ量子是自由电子激光器腔内辐射与电子逆康普顿散射时产生的。使用交叉通道腔可显著提高腔内辐射功率，从而提高γ辐射功率．并且可消除腔镜厚层损耗，解决了硬辐射输出问题。     

大阪自由电子微光研究所的自由电子激光研究

大阪自由电子激光研究所由日本关键技术中心计划建议，计划结束后，由几个组织机构在此联合工作，该所的自由电子激光器有0.27-50μm以上宽阔的可调谐波长区，正用于各种研究领域。该装置除作了用户装置基本应用外，还努力向短波长扩展，提出了带微型摇摆器和种子源X射线的自放大自发辐射自由电子激光器方案，并在这方面进行研究，微型摇摆器的基础开发接近完成，种子源X射线将采用光产生的等离子体X射线，本文给出该所目前的研究状况。     

大阪自由电子激光研究所的自由电子激光研究

大阪自由电子激光研究所由日本关键技术中心计划建立，计划结束后，由几个组织机构在此联合工作。该所的自由电子激光器有0.27-50靘以上宽阔的可调谐波长区，正用于各种研究领域。该装置除作为用户装置基本应用外，还努力向短波长扩展。提出了带微型摇摆器和种子源X射线的自放大自发辐射自由电子激光器方案，并在这方面进行研究。微型摇摆器的基础开发接近完成。种子源X射线将采用激光产生的等离子体X射线。本文给出该所目前的研究状况。     

等离子体尾波场摇摆器自由电子激光

自由电子激光的小型化和实现激光短波长一直是自由电子激光领域的研究热点,而短周期、强场摇摆器是解决此问题的行之有效的途径。文章分析了利用等离子体尾波场作为自由电子激光摇摆器的机制,推得自由电子的自发辐射谱,利用麦迪定在线阵列理论求得电子的受激辐射公式,得到小信号增益。     

静电摇摆器自由电子激光的自发辐射

基于静电摇摆器中电势场的一种典型二维模型 ,在小振幅振动情况下讨论了相对论电子束在其中的运动规律 ,计算得到了该类型自由电子激光的自发辐射谱。上述结果与平面磁摇摆器有类似的形式     

一种SASE-FEL用摇摆器机制探讨

利用带电粒子在均匀等离子体中传播时,在其后激发的尾波场作为自发辐射自放大自由电子激光(SASE-FEL)的摇摆器,称为尾波摇摆器。分析了此摇摆器在工作机制及其相应的周期、场强度,根据SASE-FEL理论计算了其增益长度Lg,并和APS的SASE实验参数作了比较。     

基于超腔技术的高亮度激光同步辐射分析

提出了一种超腔的新技术方案,利用康普顿散射理论计算了基于超腔技术的激光同步辐射(LSS)波长以及单个电子的光子产额和辐射功率,讨论了电子束品质和激光功率损耗对激光同步辐射的总光子产额和总辐射功率的影响.结果发现,利用3.5 GeV电子束和远红外激光进行康普顿垂直散射可以获得能量10.975 MeV的γ射线,单个电子产生的光子产额与激光功率和入射波长成正比,与光束的截面积成反比.单个电子的辐射功率与激光功率和Lorentz因子的平方成正比,与光束的截面积成反比.     

无镜自由电子激光器实现"饱和"发射

美国阿贡实验室的一个科研小组在无镜单通自由电子激光器中已达到自放大自发辐射饱和，其波长比从前这种无镜自由电子激光器的记录短1000倍以上。该小组展示了在可见光波长（530 nm)和紫外波长（385 nm)上指数增长和饱和的预言。该室研究人员报导了他们在Stephen Milton和Efim Gluskin领导下。逐步向X射线自由电子激光趋近的过程。同步辐射研究的历史仅有45年，真正的突破也只在屈指可数的几年里。据阿贡先进光源实验室副主任David Moncton说，他们的工作是突破中的一项。与普通激光器不同，该室的无镜自由电子激光器用强流电子加速器和…     

自由电子激光器的进展

一、进展概况高功率短波长和波长连续可调高功率激光器一直是激光研究的两个主要方向,自由电子受激辐射正是为实现这种目的的一种新途径.原理上,利用自由电子受激辐射可以实现从微波至X射线、γ射线宽波长连续可调的高功率、高效率微波与光激射器.因此,它已引起人们的普通重视.早在1933年,有人根据量子理论提出利用"摆动"或"波动"电子束与电磁波相互作用产生"受激散射"的概念.两个散射区域分别为:(1)康普顿散射:两波互作用(或单个电子互作用);(2)拉曼散射:三波互作用(或集团电子互作用).1951年莫茨(Motz)提出自由电子受激辐射理论.他认为,当电子行经电场或磁场时产生辐射,辐射的频率取决于电子的速率,电子能量从1兆电子伏到1千兆电子伏范围内可产生从微波至硬X射线频谱.他认为,将电子束聚焦,可以使一群电子相干地辐射,相干辐射功率比非相干辐射约高     

一种由强光担任摇摆器的新型自由电子激光器及其增益分析

提出了一种由超短脉冲双光束担任摇摆器的自由电子激光器的原理及设计方案,并在单电子近似的基础上给出了计算其增益的联立方程组,以用于数值模拟.指出了实现一种紧凑、廉价的可调谐光源的可能性.     

Principles of gyrotron powered electromagnetic wigglers for free-electron lasers

The operation of free-electron lasers (FEL's) with axial electron beams and high-power electromagnetic wiggler fields such as those produced by high-power gyrotrons is discussed. The use of short wavelength electromagnetic wigglers in waveguides and resonant cavities can significantly reduce required electron beam voltages, resulting in compact FEL's. Gain calculations in the low- and high-gain Compton regime are presented, including the effects of emittance, transverse wiggler gradient, and electron temperature. Optimized scaling laws for the FEL gain and the required electromagnetic wiggler field power are discussed. Several possible configurations for FEL's with electro-magnetic wigglers powered by millimeter wavelength gyrotrons are presented. Gyrotron powered wigglers appear promising for operation of compact FEL's in the infrared regime using moderate energy (<10 MeV) electron beams.     

三毫米波喇曼自由电子激光器实验研究

研制出新型小周期波荡器，报道三毫米波拉曼自由电子激光器实验。采用Ｉｃｍ周期双绕螺旋线波荡器，在相同加速器能量下，自由电子激光输出波长由８ｍｍ缩短到３ｍｍ。输出功率为１ＭＷ，效率为０．６６％。     

A novel small-period wiggler and simulations of its free-electronlaser

A small-period wiggler constructed of edgy-wound bifilar-helical conducting sheets with ferromagnetic cores, which is intended for free-electron lasers, is presented. The performance characteristics of the wiggler fields with a 100 mm period are measured. A field as high as 1500 G has been obtained. Free-electron lasers with this small-period wiggler have been investigated numerically with a three-dimensional nonlinear theory. Simulation results estimated that a radiation power of 20.2 MW and a frequency of 170 GHz with an efficiency of 5.1% can be obtained. It is feasible to make Raman free-electron lasers with this type of wiggler operating in the millimeter and submillimeter wavelength range with a relatively low electron energy (<500 keV) beam     

A staggered-array wiggler for far-infrared, free-electron laseroperation

A staggered-array wiggler for a far-infrared free-electron laser (FEL) has been built at Stanford, and its magnetic properties have been tested. This type of wiggler has several desirable features: high wiggler field at short wiggler periods, wavelength tuning by a solenoid current, electron beam confinement by a solenoid field, and looser machining tolerances. A 10.8-kilogauss peak wiggler field has been measured at a 7.0-kilogauss solenoid field for a 1.0-cm wiggler period and a 2.0-mm gap. The small-signal gain has been calculated analytically and by computer simulation for a 0.5-m long wiggler. For an 8-A, 9-ps current pulse and a 3.3-MeV electron beam, 5-dB gain is predicted. Twenty- to thirty-percent wavelength tuning can be achieved by adjusting the solenoid field and still maintain reasonable small-signal gain. The pulsed-wire technique was employed to test the field uniformity of this novel wiggler, and the measured field variation was about 1%     

等离子体波摆动器中电子运动的混沌特性

本文用Ｐｏｉｎｃａｒｅ截面及Ｌｙａｐｕｎｏｖ指数两种方法，研究了新型的等离子体波摆动器中电子运动的混沌特性，结果表明，当摆动器强度增大时电子从规则运动向混沌状态发展，这是提高自由电子激光输出功率时必须解决的一个重大课题。     

Results of the Los Alamos free-electron laser experiment

A free-electron laser (FEL) amplifier experiment to test the performance of a tapered wiggler at high optical power has been successfully completed. A well-separated two-component electron energy distribution has been obtained that is characteristic of a tapered wiggler. Energy distribution spectra and extraction efficiencies have been measured as a function of initial electron energy, energy spread, emittance, optical power, and spatial and temporal misalignments of the laser and electron beams. A maximum efficiency of ∼ 4 percent was measured, and good agreement of efficiency with a one-dimensional theory was obtained.     

Influence of Heat-radiating on Multi-photon Compton Scattering High-energy Electron

Using the model of the inverse Compton scattering between high-energy electrons and heatradiation photons, the influence of heat-radiating photons on multi-photon Compton scattering high-energy electrons is studied. The results show that the energy loss, power loss, light resistance and light pressure of the high-energy electron formed by heat radiating are all proportional to the temperature T^4 of the vacuum cavity of the electron,the Lorentz factor γ^2 of the high-energy electrons, the scattering section of the electron and the number of photons acting at the same time with high-energy electrons. A good method for lessening the energy loss of the high-energy electron by using the one-photon Compton scattering between high-energy electrons and heat radiation photons is proposed.     

Free-electron lasers with electromagnetic standing wave wigglers

A detailed analysis of the electromagnetic standing wave wiggler for free-electron lasers (FEL's) is conducted for both circular and linear wiggler polarizations, following a single-particle approach. After determination of the unperturbed electron orbits in the wiggler field, the single-particle spontaneous emission spectrum and subsequently the gain in the low gain Compton regime (using the Einstein coefficient method) are explicitly calculated. This analysis results in a clear understanding of the resonance conditions and the coupling strength associated with each resonance of this type of FEL. In particular, a striking feature obtained from this investigation is that the electromagnetic standing wave wiggler FEL, under certain circumstances, exhibits a rich harmonic content. This harmonic content is caused by the presence of both the forward and backward wave components of the standing wave wiggler field. In addition, the nonlinear self-consistent equations for this type of FEL are also presented, permitting further investigation of it by the theoretical techniques and numerical codes developed for conventional FEL's.     

Tailor‐Made Polymer Multilayers

The fabrication of multilayer assemblies from polymeric compounds is an important tool for precise control of film architecture on the nanoscale. In this report, a general, novel approach for the preparation of well‐defined polymeric multilayers is described. To achieve this, sulfonyl‐azide group containing polymers are first generated and deposited as thin films onto solid (organic) substrates. Upon thermal activation, the system crosslinks and binds to the substrate via C–H bond insertion. Through step‐and‐repeat procedures, multilayer assemblies are then generated where all the individual layers are linked to each other. As the assembly process does not require any specific molecular interactions, the described process represents a general strategy to generate tailor‐made multilayer surface coatings with wide range of film thickness and composition.