振镜激光扫描测量系统误差分析与补偿

振镜扫描系统因其具有高速和高精度等优点被广泛应用于激光快速成型、激光精密打标和激光扫描测量等诸多领域,但因振镜系统的引入而存在系统测量误差。鉴于此,首先搭建线激光一维振镜扫描系统并采用双棋盘格标定板的标定方法对系统进行标定,然后建立系统的误差模型并对扫描过程中的测量误差进行理论分析,最后针对振镜转角误差提出一种基于查表法的补偿方法。实验结果表明,当测量工作距离为250 mm左右时,误差补偿后,中心距离的方均根误差从0.733 mm降低至0.061 mm,标准差从0.200 mm降低至0.060 mm,说明该方法能够显著提高系统的测量精度和鲁棒性。     

五角棱镜在建立大尺寸平面基准中的应用

从五角棱镜的原理和特性出发，叙述了利用五角棱镜扫描建立大平面基准过程中，由于加工角差和当五角棱镜相对入射光束有相对运动时其出射光束的横移对平面基准的影响，提出了用衍射成像技术消除光束横移，数据计算修正棱镜的角度差的影响。     

小尺寸平面源的误差分析

基于Helmholtz方程的严格远场解，讨论了大发散角光辐射远场振幅和相位对于源包络扰动的依赖关系，并推导了远场振幅、相位误差公式．结果表明，远场振幅和相位误差必须用源的“误差面积”来描述；在远场主要辐射区（即傍轴区），振幅和相位对于源包络扰动不敏感，而在远轴区较敏感． 关键词：     

数字平面检测系统误差和精度评价方法的研究

通过对光学平面玻璃样品表面检测结果的分析，对激光数字平面检测系统中，应用泽尼克多项式进行平面分析的系统理论误差以及被测表面形状类型的判别方法进行了深入的研究，并应用误差分析理论，提出了一个在“泽尼克像差空间”确定激光数字平面检测系统精度的理论和方法。     

小尺寸平面源的误差精确分析

基于Helmholtz方程的严格远场解和源的“误差面积”描述方法,讨论了大发散角光辐射远场振幅和相位对于源包络扰动的依赖关系,讨论了由于源振幅扰动而产生的远场误差,建立了一种恰当的描述远场误差的方法.模拟实验表明,在“相对误差面积”的基础上,可以结合利用“离轴距离”来精确描述源误差和分析远场误差,利用“判据点”可以判断离轴误差的存在.     

大尺寸绝对距离测量的现状及发展

大尺寸绝对距离测量技术是解决工业生产中大型零件高精度测量的重要手段。本文介绍了该技术的基本原理及国内外发展现状，并对影响测量精度的三个重要因素作了分析和讨论，并预言超短波Ｘ激光、自适应光学及集成光学技术将会在该领域得到广泛应用     

高精度基准平面建立方法分析

基准平面的确立,是进行表面参数评定的基础;建立理想的基准平面,在几何量形位公差检测及相关工程测量方面具有重要作用.为了建立高精度的激光扫描基准平面,对扫描平面形成过程中光束的传播进行了详细分析;根据光学矢量反射定律,推导出了扫描误差的理论公式;在此基础上揭示了误差补偿的基本原理,导出了用于补偿扫描机构产生的扫描误差的理论公式;提出了据此准则进行设计的扫描机构的模型.分析表明,用激光及其扫描装置建立光学基准面时,扫描误差是不可避免的,这种误差不加补偿,则最终将引入基准光学平面影响基准精度,进而降低参数的评定精度;借助于所推导的误差补偿公式,是可以补偿这种误差的,这对于建立高精度的扫描基准平面具有理论指导意义.     

像质补偿在高分辨物镜精密装调中的应用

根据高分辨物镜各个光学元件的实测数据,应用轴向补偿和旋转补偿法,在仿真精密装调过程中得到了物镜轴向补偿器的最优值和各元件的最佳旋转角度。仿真结果表明,在97.7%的置信区间内,物镜各视场波像差RMS值从补偿前的0.087λ(λ=632.8nm)减小到了补偿后的0.040λ。依据获得的参数对物镜进行了装调实验,结果表明,激光干涉仪测得的物镜各视场波像差RMS值介于0.050~0.082λ之间,基本达到了衍射极限的分辨率要求,验证了像质补偿方法的有效性。     

大尺寸金属氧化物TFT面板设计分析

根据最基本的2T1C像素电路,建立了TFT各参数与AMOLED面板限制因素的计算模型。详细分析了AMOLED显示尺寸与TFT迁移率、金属方块电阻、刷新频率以及器件结构的关系。在大尺寸高分辨率AMOLED面板设计中,信号线RC延迟是主要限制因素。TFT迁移率的提高在一定范围内对大尺寸显示面板设计有利,降低RC延迟是实现大尺寸、高分辨率、高刷新频率显示的关键技术。开发铜布线技术和低寄生电容TFT器件结构是未来大尺寸AMOLED显示的关键技术。     

基于飞秒激光模间拍频法的大尺寸测距方法

本文基于飞秒激光模间拍频法实现多波长相位式绝对距离测量, 通过改变光频梳重复频率合成波长扩大测距量程, 并采用监测臂和双快门切换系统补偿和消除由电路产生的相位差单向漂移和大幅抖动. 实验中以20倍重复频率的拍频进行测量, 在30 min内相位测量的标准偏差为0.022°; 与双频激光干涉仪比对1125 mm行程内位移测量结果, 测距精度优于50 μm; 实验验证了合成波长方法扩大量程方案的可行性, 获得的测距重复性优于3 μm, 该系统理论上可扩展量程至7.5 km.     

Adaptive phase compensation for ultracompact laser scanning endomicroscopy

We present an approach to laser scanning endomicroscopy that requires no moving parts and can be implemented with no distal scanners or optics, permitting extremely compact endoscopic probes to be developed. Our approach utilizes a spatial light modulator to correct for phase variations across a fiber imaging bundle and to encode for arbitrary wavefronts at the distal end of the fiber bundle. Thus, it is possible to realize both focusing and beam scanning at the output of the fiber bundle with no distal components. We present proof of principle results to illustrate three-dimensional scanning of the focal spot and exemplar images of a United States Air Force resolution test chart.     

Speckle analysis in laser scanning display system

The theory of speckle formation in laser scanning display system is established based on the averaging effect of eye response as laser beam scanning through an eye resolution spot. It is analyzed that speckle reduction can be obtained by averaging states of speckle during scanning. The theoretical results show that a smaller correlation length of screen surface and the narrowing of laser beam in scanning direction can reduce speckle contrast for this system.     

测量大口径光学元件反射率用精密扫描系统误差分析

为测量高能激光传输系统中大口径高反射率光学元件的反射率,设计了一种大口径光学元件二维扫描的精密测量系统。介绍了该系统的结构及其工作原理,分析了影响系统测量精度的因素,从理论上分析了扫描系统的系统误差对测量精度的影响,结果表明在垂直于光束传播方向上,水平偏差在0.29 mm时,测量误差在10-6量级;腔长的变化量较小时,可通过对衰荡腔腔镜的调节,实现对旋转轴偏差的补偿及对系统的精细调节。通过拟合处理光强与时间的数据得到对应的一次指数函数拟合曲线,并通过计算得到衰荡时间和反射率,经过对比分析可知,该误差分析方法能比较有效地测量腔镜的反射率,并能减小实验数据本身带来的误差。     

Design and analysis of large-core high-GVD planar optical waveguide for dispersion compensation

We present a large-core planar optical waveguide design showing high group velocity dispersion (GVD). The design is based on a coupled asymmetric dual-core structure with an additional layer of over cladding. The resonance between the two dissimilar cores, namely, core-1 and core-2, has been utilized to achieve high GVD. The core separation controls the magnitude of the GVD. The resonance wavelength can be fine tuned by varying the parameters of the core-2. The over-cladding helps in maintaining high GVD even with large core-1. We show a GVD of 7.8×10⁻²⁵ s²/mm with the core-1 size as large as 6 μm. Such a structure should find applications in the design of high-power integrated-optic dispersion compensators for optical telecommunication and ultrafast waveguide lasers.     

Microprocessor-controlled laser scanning system for annealing of semiconductors

An apparatus for scanning the output radiation from a 5 W argon ion gas laser across a sample surface has been developed. A microprocessor was used to control the x and y axis reflectors. Laser scanning of a sample in six different patterns, and any combinations of these patterns, has been achieved. Scan rates of up to 33.6 degrees per second with a resolution of 0.034 degrees per step have been obtained. The benefits and limitations of such a system are discussed.     

共聚焦显微镜激光高速扫描控制系统设计及实现

 在传统光学扫描方法基础上,有效地将检流式与共振式光学扫描振镜结合起来,提出一种速度可达4 M/s采样率的高速激光扫描方法,并基于单片机系统设计搭建了系统控制硬件平台,编写了上位机端和下位机端应用软件。实验结果表明:该控制系统扫描速度快,性能稳定可靠,能够应用于共聚焦显微镜,实现实时扫描成像 。     

Multi-frequency AOM for multi-beam laser scanning exposure system

Digital printing systems recorded on films or computer to plates (CTPs) have been required to improve their productivity and image quality. Under the circumstance, a printing technology of the multi-beam laser scanning for the drum capstan system, which is almost the same as optics configuration as the flat bed system, was developed using a newly developed multi-frequency acousto–optic modulator (AOM) as a key device instead of ultra-fast scanning devices toward a main scan direction. The multi-frequency AOM was developed with phased array-type transducers, achieving a wider bandwidth of over 160 MHz. The design consisted of a simultaneous three beams generation with interlace scan to avoid the beat effect by adjacent Doppler-shifted beams, which consequently attained the fastest recording speed of 5.0 mm/s compared with 2.0–3.0 mm/s of existing systems in those days. Furthermore, a couple of critical parameters of the multi-frequency AOM are studied, for example, a treatment of third-order intermodulation and also beat effect in connection with photosensitive media. As a result, the necessity of interlaces scanning to obtain good image quality without beat effect and also to allow a lower laser power to apply is proposed.     

Subwavelength ripple formation on planar and nonplanar surfaces by femtosecond laser scanning

The self-formation of periodic subwavelength ripples by linear polarized femtosecond laser scanning planar and non-planar tungsten targets on the employed laser wavelength, scanning speed, and energy fluence are examined systematically. The results show that, for a certain laser wavelength, the scanning conditions have no obvious effect to the morphological features of grating structures in the threshold range of laser fluence. The spatial structured period of gratings can be self-consistently interpreted by recently presented physical model of surface two-plasmon resonance. The subwavelength structures on cylindrical surface would be a good method to realize unique surface functions on complex surface of micro-devices.     

五角棱镜补偿法加工工艺研究

由于五角棱镜两B棱的投影夹角对第二光学平行差影响倍率较大且加工过程中无法测量该夹角,从而导致棱镜加工合格率较低。通过分析侧面垂直度误差及Δ45°对五角棱镜光学平行差的影响,提出一种新的五角棱镜加工工艺方法:利用最后一个加工面对前3个已加工面存在的角度误差进行一次性补偿,从而降低了对各加工面的加工误差要求。实践证明:该方法能够有效地提高五角棱镜加工的合格率和生产效率,减小加工难度,并能显著降低对加工和检测设备的精度要求。     

光谱扫描滤波法提升飞秒激光信噪比的理论分析

在时间--频率域中,啁啾脉冲被淹没在放大自发辐射等噪声中,且其瞬时频率线性分布,基于此,提出采用光谱扫描滤波的办法来提升高功率飞秒激光系统的信噪比,并以法布里--珀罗干涉仪作为光谱扫描滤波器,对该法提升信噪比的效果进行了详细的理论分析.采用短时傅里叶变换方法,研究了光谱扫描滤波器对自发辐射放大(ASE)的滤波效果,数值分析表明,在时间抖动为-2 ps到2 ps之间、光谱扫描滤波器的通带宽度为0.4 nm条件下,该法能将飞秒激光系统的信噪比提升2个量级,而啁啾信号光以超过90%的透光率通过光谱扫描滤波器;级联光谱扫描滤波方式能进一步提升飞秒激光信噪比.