6D精密摇摆台的动态参数校准

本文介绍了6D精密摇摆台动态参数校准方法.该方法采用激光跟踪仪,利用跟踪仪的高速采样特性测量出模拟台的运动姿态,根据运动姿态进行动态特性分析,解决了Stewart平台结构的动态参数标定问题.     

高加速度超精密激光外差干涉测量模型

为了精确地描述激光外差干涉在高加速度超精密测量中加速度对位移测量精度的影响机理与规律,建立了高加速度超精密激光外差干涉位移测量模型.通过分析测量棱镜三维运动对多普勒频移的影响,推导出高加速度激光外差干涉位移测量模型.理论分析和仿真实验表明,当测量加速度为9m/s2,匀加速运行的位移为500mm时,由于加速度变化引起的相对论性效应对测量精度的影响为5nm.高加速度超精密激光外差干涉位移测量模型的建立,可提高激光外差干涉在高加速度超精密测量中的测量精度,为激光外差干涉在高速和超高速测量领域的应用提供了理论依据.     

提高激光位移传感器精度的新方法

本文提出了一种新的提高激光位移传感器精度的方法 ,利用分光器对接收光强实时控制同时利用A/D转换器对像点的峰值采样 ,最大限度降低了被测物体表面给测量带来的误差 ,提高了传感器测量精度。     

激光三角测头的动态仿形跟踪扫描

对非接触式三坐标测量机仿形跟踪快速扫描方法进行了研究,分析了曲面仿形跟踪扫瞄过程中的关键技术。针对基于激光非接触测量的仿形跟踪扫瞄,提出一种确定扫描速度及跟动速度的计算方法。利用该方法对变截面回转体进行测量,其各个径向尺寸精度可达±5μm,且测量速度是接触式三坐标测量机的3倍,验证了该方法的有效性,较好地解决了自由曲面高速、高精度仿形跟踪测量的问题。     

脉冲激光光谱测试仪的设计

设计了一种基于ISP技术的线阵CCD的驱动电路和高速脉冲光谱数据采集卡,建立了一套智能化脉冲激光光谱测试系统。该系统主要由分光系统、CCD传感器、光脉冲同步信号发生器、数据采集卡及计算机等部分组成。CCD将光强信号转换为电信号输出,经A/D转换器转换后的数字信号存入数据采集卡的帧存储器中,由计算机控制进行光谱数据的分析、处理。提出了用重心法对脉冲激光器的重复频率进行评估的方法,使测量精度达到了亚像素级。对系统所用脉冲激光器谱线峰值波长的复现性进行了测量,其标准差为0.0327nm。     

一种新型便携式二维激光测振仪研究

介绍了一种新型便携式二维激光测振仪。该激光测振仪基于激光多普勒效应原理,采用激光自混合技术,能够实现对振动物体二维面内振动测量,具有出色的频率和相位响应,满足高精度和高速测量需求。介绍了该测振仪的工作原理,针对测振仪实际运用过程中两激光束间夹角易变等问题,提出了一种两激光束间夹角的校正方法,并通过大量的实验数据,证明此校正方法的有效性和准确性。     

基于激光多普勒原理的高温振动测量技术研究

为解决表面对激光反射强度极低的试件在持续高温环境下振动响应测量不准确的问题,本文提出了基于激光多普勒原理的高温振动测量技术。从激光反射信号增强、时域响应数据后处理、激光测振仪热防护三个方面进行研究,并通过试验验证了此方法的科学性和可靠性。     

激光测形装置使钢铁厂节约了成本

美国工程度量公司和美国钢铁研究所根据美国工业工艺计划开发出了一种利用激光技术对炼钢、炼铜、炼铝的耐火炉衬厚度进行高速测量的装置。激光测形装置（ICS）的激光扫描速度超过每秒8000点,其形状分辨率非常高,可对炉膛高度进行高精度测量。此外,测量时间在1-6min之间,是原有设备的10倍。快速的原位反馈免除了因检查而耗去的停炉时间及不必要的重修炉衬时间,延长了设备寿命而且确保了操作安全。     

PCI总线在数控激光加工系统中的应用

PCI总线标准已经成为PC机的主要总线标准，它在三维激光成型、高速激光打标、激光切割等需要高速图形处理的数控激光加工系统中有着广阔的应用前景。文章分析了PCI总线应用中的技术难点，提出了解决方法，并为高速激光打标机设计出了图形处理卡，加工效率提高25%～30%。     

激光三角扫描法检测微刻槽

本文介绍一种激光三角扫描法微刻槽检测系统。该系统以激光三角法为基础 ,采用激光光斑能量细分方法 ,有效地解决了激光三角法由于光斑直径过大而引起的横向分辨力不足的问题 ,并容易做到微型化 ,适用对任意非镜面材料表面划痕的在线测量     

kHz dye laser for use with ultrafast laser systems

We have constructed a cavity-dumped dye laser optimized for use with kHz repetition rate ultrafast lasers for performing experiments on atomic and molecular systems. The dye laser is inexpensive, robust, and requires little pump energy, making it ideal for experiments requiring multiple excitations for state preparation.     

不同光束移动速度下的激光淬火有限元分析

为研究不同激光淬火处理条件下激光淬火温度场和物相结构,运用ABAQUS/Standard对激光淬火处理AISI4140钢进行了有限元模拟,并结合实验进行了验证.结果表明：激光淬火材料最高温度并不在光束中心,而是出现在距激光束中心2 mm的位置,且不随着光束移动速度的增大而改变位置;在激光束最高温度恒定为1150℃情况下...     

Development of a pumping laser system for x-ray laser research

A two-beam chirped-pulse-amplification Nd:glass laser system dedicated to x-ray laser research is described. Each beam provides an output energy of 20 J with a typical pulse duration of 1.3 ps. A prepulse of variable duration is generated by use of a novel, to our knowledge, optical system. A reflection optical system, comprised of an off-axis parabolic mirror and a spherical mirror, produces a line focus with 6-mm length and 165-microm width without chromatic aberration. By use of this pumping laser system, the nickel-like silver x-ray laser at a wavelength of 13.9 nm has been demonstrated.     

An industrial approach of laser polishing with different laser sources

Surface finishing of dies and molds is one of the most interesting applications of laser polishing process. Because of the variety of materials used in die and mold manufacturing, as well as the different surface topographies, in each case, it is necessary to use appropriate process parameters. The presented work focuses on the study of laser polishing process on three commonly used materials in the manufacture of dies and molds, such as tool steels AISI D2 and AISI P20, ductile cast iron GGG70L and LaserForm ST‐100, a specific material developed for plastic injection mold making. Experimental studies were carried out determining the influence of the energy density on the roughness reduction rate. A key point that has a direct impact on the resulting surface roughness is the initial surface finishing of the material before laser polishing. In order to determine the degree of influence, experimental studies were conducted on two steels, AISI H13 and AISI P20, which are typically used in mold making industry. The experimental tests showed that a random distribution of peaks and valleys allows more homogenous material melting and gives as result a smoother surface after laser polishing.     

Biological laser action

The narrowing of the spectral linewidth and the increasing of the peak intensity characteristic of laser action were observed in emission spectra of dye-infused biological tissues. The tissue was infused with a solution of Rhodamine 640 perchlorate in ethanol and then excited with frequency-doubled Q-switched Nd:YAG laser pulses. The dependence of emission linewidth on the excitation radiant exposure and dye concentration was investigated. Laser action was also observed in biologically compatible fluorescein sodium dye dissolved in phosphate-buffered saline mixed with scattering polystyrene spheres. The sharp spectral peaks of laser action in tissues may find applications in the detection of superficial disease.     

Hankel-Bessel laser beams

An analytical solution of the scalar Helmholtz equation to describe the propagation of a laser light beam in the positive direction of the optical axis is derived. The complex amplitude of such a beam is found to be in direct proportion to the product of two linearly independent solutions of Kummer's differential equation. Relationships for a particular case of such beams-namely, the Hankel-Bessel (HB) beams-are deduced. The focusing of the HB beams is studied.     

Single-nanowire single-mode laser

We demonstrate single-mode laser emission in single nanowires. By folding a 200 nm diameter CdSe nanowire to form loop mirrors, single-mode laser emission around 738 nm wavelength is obtained with line width of 0.12 nm and low threshold. The mode selection is realized by the vernier effect of coupled cavities in the folded nanowire. In addition, the loop structure makes it possible to tune the nanowire cavity, opening an opportunity to realize a tunable single-mode nanowire laser.     

Distributed laser refrigeration

A 250-mum-diameter fiber of ytterbium-doped ZBLAN (fluorine combined with Zr, Ba, La, Al, and Na) has been cooled from room temperature. We coupled 1.0 W of laser light from a 1013-nm diode laser into the fiber. We measured the temperature of the fiber by using both fluorescence techniques and a microthermocouple. These microthermocouple measurements show that the cooled fiber can be used to refrigerate materials brought into contact with it. This, in conjunction with the use of a diode laser as the light source, demonstrates that practical solid-state laser coolers can be realized.