【作者】 梁晶；

【导师】 龙兴武；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2010， 博士

【摘要】 与传统外差干涉测量法相比,多波长绝对距离干涉测量法具有测量过程无需导轨及测相无需累加计数的优势,可使干涉测量更适用于实际生产生活的需要,进一步提高了现有激光干涉测距系统的应用范围,有着较高的应用和学术价值。近年来,研究工作主要集中在如何选择合适光源组成合成波长链、高精度的相位测量、对各种误差因素的修正及如何使干涉系统实用化等方面。本论文着重围绕多波长干涉测量法中的几个关键技术展开理论和实验研究,旨在探索其设计、构建和实用化方法。主要内容包括:1.从小数重合法和多波长干涉理论出发,推导了光源在干涉系统中所需满足的级间过渡条件和使测量精度得以提高的逐级精化理论。结合对各种光源振荡特性的分析,提出了利用633nm波段He-Ne激光构成双线三频的合成波长干涉测量方案,分析了该方案的实现机理以及光源部分所要满足的条件。2.根据干涉系统中对光源的要求,特别是根据通常情况下629nm波长难以单谱线振荡输出的特性,分析了在相邻且增益相差悬殊的两谱线中选择单波长振荡的难点及以往激光器内谱线选择方法的不足。从F-P腔模理论出发,研究了标准具随着长度和反射率参数而改变的透射特性,提出了用内置F-P标准具法在激光器内选择谱线的方案。给出了对于增益悬殊的相邻谱线,F-P标准具实现选线所需要满足的长度和反射率公式,并用高斯光束传输理论仿真分析了内置F-P标准具后激光器的透射特性。3.采用内置F-P标准具法,研制出可实现629nm单波长振荡输出的激光器。通过调整F-P标准具在激光器内的倾斜角可以实现633nm和629nm两波长交替输出。实验测量了该激光器在不同谱线振荡时随电流改变的输出功率变化;用外置F-P扫描干涉仪检测了两波长分别振荡时的模式分布;并进一步用调节激光器腔体PZT的方法测量功率调谐曲线进一步证明前述模式分布结论的正确性;使用小抖动方法对629nm波长He-Ne激光器进行稳频实验,并给出了稳频实验结果。4.根据干涉方案中对光源的需求,详细分析了633nm双纵模He-Ne激光器内存在的模式特征。从理论上分析推导了在考虑模牵引效应后,双纵模激光器内两纵模的拍频不确定度与其中一个单纵模频率不确定度之间的关系。用双纵模等光强法对该激光器实施了稳频,并和高稳定度的碘稳激光器作了双纵模拍频和单纵模的稳定度测试。5.用629nm和633nm波长激光组成117μm合成波长进行绝对距离动态及静态测量实验,并从合成波长、大气折射率波动及测相电路三个方面对实验结果作了误差分析。更多还原

【Abstract】 The absolute distance measurement by multiple-wavelengths has much more advantages over the traditional heterodyne interferometry at least in two aspects: needlessness of guidelines and directly phase detecting while measuring. It could not only largely meet the demand of metrological needs but also be used almost everywhere in real life. Thus, it enjoys a good academic value and application. In recent years, research works mainly focus on the selection of synthetic wavelengths, high precision measurement of phase, the correction of external disturbances, and commercialization of the interferometry. Therefore, in this thesis, theoretical and experimental studies on the several techniques in interferometry are presented. The main work included as follows:1. Based on the classical theory of excess fraction method and multiple wavelength interference, the transition fitting condition and the accuracy refining theory are conducted. By analysis of the oscillating properties of various light sources, we come up with a blue print of interferometer by using the 633nm band He-Ne laser, constructing synthetic wavelengths with 2 lines and 3 frequencies. The demands of the light sources in interferometry are analyzed.2. According to the demands of light sources in interferometry, considering of the difficulty of the single 629nm oscillation in common He-Ne laser as well, we analyze the hardship of line selection particularly in two nearby transition lines with gains of sharp contrast. Shortcomings of usual line selection methods are discussed as well. Based on the F-P etalon’s transmittance theory, a new method to select the nearby lines by using an internal F-P etalon in He-Ne laser is presented. By this method, the general line selection condition is conducted, which must be in accordance with the length and refractivity of etalon. At last, by using the Gaussian beam transmission theory, we simulate the transmitting properties of light in laser cavity.3. By using the line selection method mentioned before, a single line 629nm He-Ne laser with an internal F-P etalon is designed. The laser can emit 629nm and 633nm line respectively when the angle of etalon is adjusted. Experiments are done such as, detecting the output power of laser while the current is changing, modes scanning by an external F-P interferometry. Furthermore, by scanning the laser cavity, we measure the modes of light in laser, which prove our conclusion of modes distribution as well. A frequency stabilization method by small mechanical dither is applied to stabilize the 629nm He-Ne laser. Experiments results of frequency stabilization by that method are also provided.4. The stability and mode properties of beat frequency in the double-mode He-Ne laser are discussed. Considering of the mode pulling effect, we conduct the relationship between the stability of the single mode and the beat frequency theoretically. By using PID control method, we stabilize the double-mode He-Ne laser with equal light intensity. Experiments are done to compare with a standarded iodine-stabilized laser to testify our conclusion.5. Experiments of absolute distance measurement by using 629nm and 633nm wavelength, consisting of a synthetic wavelength of 117μm, both in dynamic and static situations are presented. The errors caused by the synthetic wavelength, the refractive turbulence and the electronic turbulence are discussed in detail.更多还原