红外自由电子激光谐振腔的准直安装  

Alignment and Installation for Resonant Cavities of FELiChEM

作　　者：王巍[1] 李笑 罗涛 陈佳鑫 李和廷[1] 何晓业[1] Wang Wei;Li Xiao;Luo Tao;Chen Jiaxin;Li Heting;He Xiaoye(National Synchrot ron Radiation Laboratory,University of Science and Technology of China,Hefei 230029,Anhui,China)

机构地区：[1]中国科学技术大学国家同步辐射实验室,安徽合肥230029

出　　处：《中国激光》2022年第23期80-87,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(21327901);重要方向培育基金(WK2310000085)。

摘　　要：基于可调谐红外激光的能源化学研究大型实验装置的核心器件是两套自由电子激光振荡器,能够产生覆盖2.5~200.0μm波长范围的连续可调的中红外和远红外激光光谱。每套振荡器包括一个波荡器、一对由位姿可调的镀金球面反射镜和真空室构成的谐振腔以及三个POP-IN探测器。在准直过程中,需要保证波荡器磁中心、金属球面反射镜轴心和电子束流中心线达到很高的共轴精度以实现激光的饱和输出。为了实现对波荡器束流的监测,需要通过准直的手段保证反射镜的光可以通过三个由步进电机控制的POP-IN上的直径为1 mm的小孔。采用激光跟踪仪配合光电自准直仪,对谐振腔进行了准直,谐振腔反射镜的横向倾斜度小于50μrad,横向离轴偏差小于0.1 mm。使用激光跟踪仪结合准直望远镜,实现三个POP-IN的工作点位置与电子束流中心线共轴,共轴精度为0.15 mm,并通过激光器搭建在线准直系统,将真空外准直激光照射到腔体内部以调节反射镜姿态。开展了离线标定实验和现场安装,红外自由电子激光装置的顺利出光证明所提方案是可行且可靠的。Objective The FELi Ch EM is an infrared free electron laser(FEL)facility,currently under construction,and it consists o f two oscillators that generate middle-and far-infrared lasers covering the spectral range of 2.5--200.0μm.Each o scillator includes an undulator,a pair of gold-plated spherical mirrors with adjustable poses,a resonant cavity composed of a vacuum chamber,and three POP-IN detectors.The magnetic axis of the undulator,optical axis of the resonator,and electron beam propagation axis must be aligned with high precision to achieve saturated lasing.To monitor the beam current,the reflected light from the spherical mirrors must pass through three 1-mm holes on the POP-IN detectors controlled by stepper motors via a collimating telescope.According to physical calculations,the transverse inclination of the resonator mirror and the transverse off-axis deviation should be less than 50μrad and 0.1 mm,respectively,ensuring that the three POP-IN operating points are coaxial with the electron beam centerline and the coaxial accuracy is 0.15 mm.Methods Through the analysis of relevant engineering experience and actual measurement conditions,we analyze and i nstall the two oscillators based on a laser tracker,photoelectric autocollimator,and collimating telescope.Initially,a laser tracker is used to install major equipment,such as magnets,undulators,vacuum chambers,and mirror supports,based on the installation control network.The installation accuracy is better than 0.15 mm and 0.1 mm in the beam and transverse directions,respectively.In accelerator physics,the transverse direction refers to two directions perpendicular to the beam direction.After this equipment is installed,a laser tracker and photoelectric autocollimator are used to install and adjust a gold-plated spherical mirror.First,based on the laser tracker,the photoelectric autocollimator is positioned in the space coordinate system with high precision to ensure that the axis of the photoelectric autocollimator is coaxial with the optical axis of the

关 键 词：测量 红外自由电子激光 谐振腔 准直安装 自准直仪 激光跟踪仪 

分 类 号：P258[天文地球—测绘科学与技术]