偏振分光光学天线前向散射杂光仿真测试与抑制

利用口径150mm、视场±0.17°、接收波长974nm的光学天线望远系统原理样机,搭建了试验装置并进行了实测,测量结果显示光学天线在0.35°附近及1°附近出现了两个原路回波杂光峰值.通过对两个杂光峰值的仿真分析,提出了在主镜内部增加二次斜光阑及临时挡光环的措施,消除望远系统前向散射杂光.通过分析主次镜焦距分配对光学天线望远系统杂光的影响,指出在设计中缩小主镜焦距可降低系统原路回波杂光,这对光学天线消回波杂光设计具有指导意义.     

Propagation Rule of Pulsed Light Beams through First-order Optical Systems

1.IntroductionInthepastfe\\'ycarsltllcil1tcnsity-momentsmethodandtheM2factorhavebeenre-vea1edtobeveryuscfulrotlcscribethepropagationlawandthebeamqualityofastaticlightbeam[l~Jj.Rccent1y,1ncji:1sctal.generalizedtheintensitymomentsmethodfortheSCLQ(speetral1y`"el1-centcrcdandlocallyquasi-monochromatic)pulsedlightboms[5j.Itisapparentthatthosercsu]tsubtainedinreferenceL5]areon1yvalidfortheso-calledquasi-monochromaticlightbeamsandarenotvalidforgeneralpolychromaticpulsedlightbeams,esPeciallyaredono…     

关于声光效应光束偏转角的实验研究

对声光效应中光束偏转角进行了一系列实验研究.基于传统声光效应的基本原理,建立了光束偏转角理论模型并进行了相关计算.在此基础上进行声光效应的布拉格衍射实验.大量实验结果显示,所测量到的光束偏转角和理论值存在一定的差距.     

Dual beam method for laser welding of galvanized steel: Experimentation and prospects

Laser welding of zinc-coated steel sheets in lap configuration poses a challenging problem, because of the zinc vapours spoiling the quality of the weld. In continuation to the earlier work, the novel solution of dual laser beam method for lap welding of galvanized steel sheets is discussed here in view of the recently obtained observations and ensuing concerns. In this method the precursor beam cuts a slot, thus making an exit path for the zinc vapours, while the second beam performs the needed welding. The metallurgical analysis of the welds is encouraging showing absence of zinc in the welded area. In the current work on this technique, new experimental results have been obtained verifying the earlier observations. Along with this, the possibility of using a transversely split-up beam for the welding purposes with this approach is discussed and analyzed in this paper. This new technique is expected to be very useful in prospective industrial applications requiring higher welding throughput along with the needed quality.     

Second-harmonic wave induced by vortex beams with radial and azimuthal polarizations

The author investigated second-harmonic (SH) wave patterns generated by focused vortex beams with radial and azimuthal polarizations. Expressions for electric field components near the focus through a dielectric interface were obtained based on vector diffraction theory. Furthermore, the (110) and (001) planes of a crystal classified in the symmetry group 4?3m were considered as second order nonlinear optical medium to analyze nonlinear polarization and the intensity distributions of the SH wave in the far-field were simulated for topological charge m = 1 and 2. Numerical simulations indicated that the intensity and emission pattern of the SH wave depended principally on the electric field component and distribution near the focus. In particular, for the (001) plane, the intensity of the SH wave was strongly correlated with the existence of a longitudinal electric field.     

Interferometric monitoring of single-mode operation of a tunable injection laser

We propose a technique for rapid monitoring of single-mode operation of a tunable injection laser, based on analysis of the fine structure of the power-current characteristic obtained with self-heterodyning, using a Michelson interferometer. The technique makes it possible to determine the range for single-mode lasing and mode tuning as well as the presence of spurious optical feedback, and to estimate the coherence length. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 119–123, January–February, 2006.     

Development of diamond-based X-ray detection for high-flux beamline diagnostics

High‐quality single‐crystal and polycrystalline chemical‐vapor‐deposition diamond detectors with platinum contacts have been tested at the white‐beam X28C beamline at the National Synchrotron Light Source under high‐flux conditions. The voltage dependence of these devices has been measured under both DC and pulsed‐bias conditions, establishing the presence or absence of photoconductive gain in each device. Linear response consistent with the theoretically determined ionization energy has been achieved over eleven orders of magnitude when combined with previous low‐flux studies. Temporal measurements with single‐crystal diamond detectors have resolved the nanosecond‐scale pulse structures of both the NSLS and the APS. Prototype single‐crystal quadrant detectors have provided the ability to simultaneously resolve the X‐ray beam position and obtain a quantitative measurement of the flux.     

Design of the low energy beam transport line for the China spallation neutron source

The design of the China Spallation Neutron Source (CSNS) low-energy beam transport (LEBT) line, which locates between the ion source and the radio-frequency quadrupole (RFQ), has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74 m. This LEBT is designed to transfer 20 mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper.The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.     

大型固体激光器光束定位稳定性分析

根据 ICF驱动器系统工程的要求 ,建立光学元件运动量与靶点光束定位之间关系 ,对稳定性进行初估。运用 B类评定方法、光线追迹方法和有限元数值模拟方法进行检验和校正 ,使其更具有可行性。并从结构随机振动理论出发 ,将结构用单自由度线性系统的平稳随机振动模拟 ,实现稳定性值激励源的重分。