线电流摇摆场自由电子激光

根据经典辐射理论计算出电子在线电流摇摆场中运动产生的自发辐射强度分布；利用单粒子理论推导了自发辐射与受激辐射的关系；利用这种关系求出了电子在线电流摇摆场中运动产生自由电子激光的小信号增益。     

用自由电子激光产生高次谐波

布鲁克海文国家实验室与阿贡国家实验室已演示一种高增益谐波产生自由电子激光器 ,他们希望它能导致发展出硬 X射线激光。其原理论证实验已有叙述 ,在布鲁克海文用一 0 .5MW CO2 激光的 2 0 0 ps1 .0 6 μm脉冲作种籽脉冲。种籽脉冲在一次波荡器与 4 0 Me V电子束相互作用 ,产生能量调制。色散磁铁将此能量调制转化为相干空间密度调制 ,在第二波荡器产生 5.3μm相干光。研究者计划用 Ti∶宝石激光器的 2 6 6nm的三次谐波作种籽 ,输入该装置 ,产生真空紫外光。进一步的实验可使用更多的增益级 ,使输出提高至 X射线区。用自由电子激光产生…     

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。     

加反向导引场自由电子激光动力学理论

本文对加反向导引场自由电子激光加以描述，假定摇摆场是理想化的，分析电子的运动轨道，解得运动常数，求解符拉索夫方程得到扰动分布函数，从波方程可得色散关系，进而得增益公式，该公式近似适用于有导引场和无导引起的情况。     

高增益谐波发生器式自由电子激光器

演示了高增益谐波发生器式自由电子激光器，我们采用激光种子源的自由电子激光，经纵向杆干，放大和傅里叶变换限制在种子源激光的谐波输出，种子源二氧化碳激光在波长10.6μm产生饱和，在二次谐波波5．3μm输出放大的自由电子激光，实验证明将这种技术和方法应用到光谱的真空紫外区的理论基础，推广这种方法的最终目的的提供产生非常强的高度相干硬X射线源。     

电子在双曲函数摇摆场和轴向导引场中的运动分析

本文用扰动法来分析电子在具有双曲函数型摇摆场和轴向导引场中的离轴运动轨道和速度。发现了电子运动存在着丰富的回旋谐振频谱，有基波即磁共振和高次谐波回旋谐振和反回旋谐振，并且存在分数谐振和反谐振。     

1994年底长波自由电子激光

简短总结了长波自由电子激光的现状及其未来最重要的发展方向，为讨论方便，长波是指波长长于０．５ｍｍ。长短波间的区发并非完全随意。它们具有不同的物理过程。例如，长波中主要彩和强流电子束，因而空间电荷效应变得很重要。诚然，其主要相互作用机制通常是相干拉曼散射，而不是相干康普顿散射。另外，波长较长时，由漂移管及腔中电子束的 效应及有限横向尺寸导致的色散效应将变得重要。长波自由电子激光研究的最终目标是建立总     

二维摆动磁场自由电子激光自发辐射的频谱特性

本文对二维摆动磁场自由电子激光的自发辐射频谱进行了理论分析,并对分析结果进行了数值计算.计算结果表明,采用l(lkx=ky)值不同的二维摆动磁场,可以增强第l次谐波的自发辐射强度,从而能够有选择地实现自由电子激光的高次谐波运转.     

ANGULAR SPECTRUM PROPERTY OF SPONTANEOUS EMISSION IN A TWO-DIMENSIONAL UNDULATOR FREE-ELECTRON LASER

The angular spectrum of spontaneous emission in a two-dimensional undulator free-electron laser is analyzed theoretically. Numerical calculation shows that the 3-th harmonic spontaneous emission power density can be greatly enhanced by using a two-dimensional undulator, for which l=s, so the harmonic number can be selected by selecting l. Therefore, the higher harmonic operation of a free-electron laser can be realized selectively.     

Theory of a free-electron laser with a Gaussian optical undulator

A theoretical study of the possibility of a free-electron laser in the XUV and soft X-ray region of the spectrum, using a counterpropagaing CO₂ laser beam as an undulator, is presented. A one-dimensional model is used to evaluate the single-pass power gain of such a device. The detrimental effects due to the energy speed, emittance of the electron beam, and the diffraction of the electromagnetic undulator are explicitly incorporated in the formalism. An oscillator experiment is also considered. The solutions of the optical pulse evolution equation in the weak field, low gain, and long-electron-pulse regimes are all derived     

Influence of a step-tapered undulator field on the optical pulseshape of a far-infrared free-electron laser

The optical output of the free-electron laser for infrared experiments (FELIX), which operates in the regime of strong slippage, consists of picosecond pulses. Depending on the amount of cavity desynchronization, the optical pulse can develop substantial structure in the form of multiple subpulses. We present second-order autocorrelation measurements of the subpulses at several far-infrared wavelengths while applying a step-taper in the undulator field. The operation with a step-tapered undulator prevents the electrons from reabsorbing the optical field energy, leading to a smooth optical pulse. For different settings of the undulator the measured pulse shape and corresponding power spectrum are discussed. It is possible without decreasing the small-signal gain to produce a smooth high-power optical pulse during the whole saturated part of the machine pulse in an FEL oscillator with a reverse-step tapered undulator     

二维激光告警光学系统设计

由于现有单激光告警系统只能实现来袭激光一维的方位和波长等信息,提出了一种单激光告警系统同时测得二维方位信息和波长信息的新方法,该方法的光学系统主要由遮光罩、光栅、透镜组和面阵CCD组成,通过对来袭激光经过光栅后的一级和零级衍射光斑位置的判决,得到来袭激光二维方位和波长信息。通过理论分析说明了该方法的原理,并推导得出二维方位角和波长的测量公式,根据要求推导确定了光学元件参数,并通过实验验证了其可行性。实验结果显示波长分辨率小于10 nm,角度分辨率小于1x方向视场角为30,y方向视场角为15。     

Short-pulse effects in a free-electron laser

The Free-Electron Laser for Infrared eXperiments (FELIX) offers a unique combination of short electron bunches and long wavelengths, i.e. a slippage parameter μ_c ranging up to 10. As a consequence, pronounced short-pulse effects can be observed. In this paper the experimental observation of two of these effects is discussed, namely the occurrence of limit-cycle oscillations and the feasibility of tuning of the micropulse duration. The stable limit-cycle oscillation of the macropulse power is due to a modulation of the optical micropulse shape. This is a consequence of a combination of high optical power and short pulses. The former causes synchrotron oscillations of the electrons and the effect is, therefore, closely related to spiking phenomena. The short-pulse nature of FELIX ensures that the oscillations do not evolve into the chaotic behavior normally associated with spiking and the sideband instability. Experimental results are compared with numerical simulations     

组合式二维列阵面发射半导体激光器

设计出新型二维列阵面发射激光器,获得了室温准连续大于250mW的光功率输出。     

基于二维激光位移传感器同轴度测量方法研究

提出了非接触方式测量同轴度的方法,采用二维激光位移传感器测量空心圆柱体内表面同轴度。依据传感器的采样率对搭载被测物体的转台的速度提出了要求。同时给出了根据圆柱内表面直径选取二维激光位移传感器的方法及设计技巧。对影响测量精度的因素进行了详细分析。实验表明,该测量装置易于实现,测量精度高,方法可行。     

乙烯分子在激光场中的多光子电离及高次谐波的产生

本文运用含时密度泛函理论和局域密度近似方法,分别研究了乙烯分子在单色激光场、双色激光场中电离和高次谐波的产生。计算结果表明,在单色激光场中,乙烯分子的高次谐波谱呈现出明显的平台区和奇次谐波加强的特征：在双色激光场中,乙烯分子的电离增强而出现高电荷态几率,并伴有偶次谐波的出现。     

Optical guiding in a Raman free-electron laser

A theoretical and computational study of optical guiding in a Raman free-electron laser (of wavelength ≃ 2 mm) is given. A set of basic dynamical equations is given, including the effects of space-charge and two-dimensional diffraction, both with and without a waveguide. The results from a computer code based on these equations are reported, showing optical guiding. An experiment is proposed in the Columbia free-electron laser to measure optical guiding.     

Nonlinear theory of a quadrupole free-electron laser

The nonlinear motion of electrons in a quadrupole free-electron laser is analyzed. If the betatron frequency is close to the mismatch frequency, the three-dimensional nonlinear equations can be reduced to an integrable one-dimensional equation. To enhance the efficiency, a tapered wiggler is introduced and the electron orbits in a tapered quadrupole free-electron laser are analyzed. The conditions for the particles to remain trapped as the heat wave decelerates are found.