【作者】 许志广；

【导师】 张书练；

【作者基本信息】 清华大学 ， 光学工程， 2006， 博士

【摘要】 激光谐振腔的稳定性问题是影响激光器性能的重要研究课题,传统的谐振腔激光器对腔镜的失调非常敏感。本文研究使用猫眼谐振腔提高氦氖激光器的稳定性,及两种基于猫眼谐振腔氦氖激光器的新型位移传感器。本文的实验证明,在半外腔和全外腔结构的氦氖激光器中应用猫眼谐振腔后稳定性得以大幅度提高,其反射镜的最大允许失调角度比普通反射镜分别提高了10倍和60倍,功率漂移显著减小;当保证猫眼逆向器的凸透镜中心位于激光增益管的毛细管轴线上时,可以实现猫眼谐振腔的免调试实验,并以此为基础成功研制了半外腔和全外腔结构的免调试氦氖激光器;调整猫眼逆向器中凸透镜与凹面镜的间距可以改变输出激光的横模状态,从而保证基横模输出。对猫眼谐振腔氦氖激光器开展了深入的理论分析,包括用等价共焦腔理论分析了猫眼谐振腔中的高斯光束特性;用几何光学和矩阵光学的方法、并借用失调灵敏度参量的概念分析了猫眼谐振腔的失调特性;分别研究了尺寸误差和离轴误差对谐振腔特性的影响;对谐振腔中插入楔形元件后对谐振腔性能的影响进行研究;用牛顿-柯特斯公式求解衍射积分方程的方法分析了猫眼谐振腔的横模选择现象。各种理论分析与实验结果符合的比较理想。“位移自传感激光器系统”是猫眼谐振腔氦氖激光器应用于位移传感领域的成功范例。本文为解决仪器的长期稳定性问题做了诸多改进,使之成为能真正应用于工业领域的较成熟仪器,并将其用途拓展,可用来测量绝对量块厚度和标定电感测微仪的精度和线性度。本文提出、设计了“猫眼折叠腔”并以此为基础研制了“猫眼折叠腔——位移自传感激光器系统”。论述了其工作原理、两种结构方案和制作过程;理论分析并用对比实验验证了“猫眼折叠腔”相比普通的猫眼谐振腔更具稳定性;用该仪器进行了实际位移测量,获得了稳定而理想的两正交偏振光的功率调谐曲线;用HP5529A激光干涉仪对该仪器做了标定,证明现有仪器的分辨率为39.55nm,量程为14.4mm,线性度误差为4.2×10-5;对测量结果进行了误差分析,并提出了新电箱的设计方案。更多还原

【Abstract】 The resonating stability of a laser is always an important research project for laser performance,and the conventional resonator is very sensitive to the swing of its cavity mirrors. This thesis researches the stability of HeNe lasers by employing the cat’s eye resonator, and introduces two novel displacement sensors based on the cat’s eye resonator HeNe laser.Experiment results in this thesis prove that: in the half-external and full-external cavity HeNe lasers, cat’s eye cavity can improve laser stability greatly, enhance the maximum misalignment angles of the reflecting mirror up to 10 and 60 times respectively, and lower the power drifts significantly. If the convex lens center of cat’s eye reflector is ensured in the laser bore axis, the adjustment-free performance of the cavity can be realized, founded on which the half-external and full-external cavity adjustment-free HeNe lasers are developed successfully. When the distance between the convex lens and concave mirror is regulated, the laser beam pattern will be modulated, according to which the transverse mode patterns can be selected to assure the fundamental transverse mode operating.Theoretic analysis is carried out comprehensively for the cat’s eye resonator HeNe laser, including analyzing the Gauss beam character in the equivalent confocal resonator method; studying the misalignment character respectively in geometric method and matrix optics with misalignment sensitivity parameter; calculating the influences to the resonator introduced by the dimensional and abaxial errors; discussing the case in which a wedge-shaped element is inserted into the laser cavity; researching the transverse mode selection phenomena by solving the two-dimensional diffraction integral equation with Newton-Cotes method. The analysis results match the experiments very well.The“Displacement self-sensing laser system”is a successful exemplification applying the cat’s eye resonator HeNe laser into the displacement measuring field. Much significant improvement is carried out to solve its long-term stability problem, and make it a mature apparatus used in industry and metrology realm. Accordingly its application area is widened to be competent for measuring the gage block thickness and calibrating the linearity and accuracy of the inductance displacement sensor.An original“cat’s eye folded resonator”is built, based on which another new displacement sensor named“folded resonator--displacement self-sensing laser system”is set up, and its principle, two kinds of structures and fabrication procedure are presented detailedly. Both the theoretic analysis and comprehensive experiments show that the folded cat’s eye resonator has higher stability than the common one. Practical displacement measurements are made, ideal and stable power tuning curves of the two orthogonal polarization lights obtained. Calibration by HP 5529A laser interferometer indicates that the sensor has a high resolution of 39.55nm, a large measurement range up to 14.4mm, and a tiny linearity error of 4.2×10-5. Measurement error is analyzed and the design project of the new circuit is discussed.更多还原