It is shown that the divergence angle of pumping beam and off axis pumping and spontaneous radiation influenced the linewidth of parametric light more quickly than those of other factors did , and the linewidth of parametric light is very narrow far away from the degeneracy point , and the linewidth begins to large quickly at the degeneracy point 结果表明，泵浦光的发散角、泵浦光的偏轴泵浦、自发辐射对参量光的线宽影响较大。在远离简并点处，线宽较小，在简并点处，线宽较大。
With the development of laser techniques , the optical cavity has played an important role on monitoring laser mode , measurement and narrowing of laser linewidth , laser mode cleaner , laser frequency stabilization , optical spectrum and cavity - qed etc . , due to its advantages of ultra - low losses , high finesse and narrow linewidth 随着激光技术的发展，谐振腔由于其腔内损耗小、精细度高、线宽窄等特点，使得其在监视激光模式、测量并压窄激光线宽、激光模式清洁、激光稳频、激光光谱学、腔量子电动力学等方面起到重要的作用。
Based on these foundations , we give a perfect scheme of the bbo opos : single pass amplification coefficient of the opg under different pump intensity is calculated ; collinear type - i and type - ii phase matching tuning curve pumped by the q switch nd : yag various harmonics as well as noncollinear type - i tuning curve are calculated in details ; the effect of the walkoff for the nonlinear effect coefficient and the group velocity matching are analyzed ; the acceptance angle in parametric process is calculated ; the numerical threshold of the bbo opo is calculated ; the process of the saturation and depletion of the pump beam are analyzed ; the relationship of the conversion efficiency and reflectance of output mirror are discussed ; various linewidth controlling methods are discussed ; the improvement of the beam quality applying the unstable cavity is discussed ; and the crystal bbo design is considered 在此基础上，给出了一整套bbo - opo激光参数设计方案：计算了不同泵浦强度下的参量放大倍数；详细计算了在nd : yag调q激光器各次谐波泵浦条件下的共线类和类相位匹配的调谐曲线，以及非共线类相位匹配调谐曲线；分析了走离角对非线性系数和群速匹配的影响；计算了参量过程的允许角；计算了bbo - opo的理论阈值条件；分析了饱和与泵浦光束的消耗过程；给出了转换效率与超过泵浦阈值的倍数的关系；讨论了转换效率与输出镜反射率的关系；讨论了线宽控制的各种方法；研究了利用非稳腔改善光束质量的方法；考虑了bbo晶体的设计。
In the section of fabricating technology , i first discuss the ion beam technology . through the analysis of the effects of each parameter on the surface smoothness , profile fidelity and linewidth resolution in the process of ion etching , the suitable angle of incident ion beam , ion energy , density of ion beam and time of etching are selected combining the actual status of the mask 在制作工艺的研究方面，首先研究了离子束刻蚀技术，通过对离子束刻蚀过程中各个参数对刻蚀元件的表面光洁度、轮廓保真度和线宽分辨的影响分析，结合掩膜的实际情况选择出了合适的离子束入射角、离子能量、束流密度和刻蚀时间等参数。
Secondly , we propose and demonstrate experimentally a novel multi - wavelength erbium - doped fiber ring laser by using a mach - zehnder fiber interferometer and composite cavity . as a result , simultaneous multi - wavelength oscillations with narrow linewidth and equal wavelength span are obtained in room temperature . this device has advantageous of simple design fabrication and low cost et al 进一步，我们设计了一种新颖的多波长掺铒光纤环形激光器，这种激光器是利用mach - zenhder ( m - z )光纤型干涉仪作为梳状滤波器，并且与复合腔共同选频，获得了窄线宽、等间隔的多波长同时输出，这种激光器具有在常温工作，结构简单，成本低等优点。
Abstract : we have studied the polarization beats spectroscopy with phase - conjugation geometry in a cascade three - level system . it was found that the accuracy for the energy - level difference measurement is determined by the homogeneous linewidths of the optical transitions . under the condition for the occurrence of beating , the frequency difference of the beat between two independent light sources could exceed the laser linewidth . the measurement accuracy for laser absolute frequency could reach the same order of magnitude as the laser linewidth 文摘:研究了级联三能级系统中的相位共轭极化拍频光谱术.发现其对能级差的测量精度决定于光学跃迁的均匀增宽.在符合拍频条件时，两独立光源拍频的频差可以超出激光线宽，激光绝对频率的测量精度可达到与激光线宽同一量级
Continuous - wave optical parametric oscillators ( cw opos ) are an attractive source of coherent radiation in applications for which laser sources are unavailable or for which wide tunablity is needed , cw opos have remarkable features of operating with narrow linewidth and broad tunablity 连续波光学参量振荡器( cwopos )可以用来拓宽激光的波长范围，有较宽的调谐区域，是一种理想的产生相干辐射的装置。由于它的窄线宽和宽调谐的输出特性，也被用于光谱学、相干光通讯、量子光学等领域。
