共查询到18条相似文献,搜索用时 78 毫秒
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本课题旨在研究光学谐振腔的特性,藉以改进军用指示器/测距机用的激光系统。过去曾对负分支非稳谐振腔激光器的特性作过研究。室内试验证明它具有独特的发展前景,提出了一种新的途径来解决现存的种种问题:光束质量、工作效率和可靠性、视轴稳定性等。 相似文献
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推导了变反射率镜激光谐振腔输出光束的传输特性,求得了其光斑大小W(z),并对结果进行了分析。 相似文献
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晴天 《激光与光电子学进展》1986,23(10):14
用电子束泵浦的半导体激光器通常有宽的(10°~15°)方向性图。在激活区直径为300~500 μm的激光器中,使用外反射镜可将辐射的方向性图压缩到衍射极限,并在谐振腔中形成基横模振荡。 相似文献
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为了研究激光在高斯镜平凸非稳腔中的模式和相位特征,在SIEGMAN分析多元件非稳腔的理论基础上,采用有限元数值方法计算耦合输出镜镜面反射率为高斯分布的圆镜平凸非稳腔本征模场分布。将光场在腔内一次往返的ABCD系数代入惠更斯-基尔霍夫衍射积分方程,可以写出光场往返一次的衍射积分方程。将镜面分割成若干个等宽圆环,把衍射积分方程转化成矩阵相乘形式,经过数值计算,得到理想空腔和非共轴空腔优先起振的光场本征模式分布结果与相位特性。计算结果表明,当合适选择输出镜半径与高斯反射率分布,可以得到光斑半径为0.3cm的基模高斯光束输出,此计算结果与实验结果相符。同时也讨论了耦合输出镜对光束质量的影响。 相似文献
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Improved mode properties of unstable resonators with tapered reflectivity mirrors and shaped apertures 总被引:1,自引:0,他引:1
The use of tapered reflectivity mirrors and shaped apertures in unstable resonators is shown to be an effective method for improving the mode properties. Mode intensity and phase profiles are smoothed and the mode discrimination ratio is increased. Results are presented illustrating the importance of diffracted waves from sharp mirror edges in determining these mode properties. A simple expression for estimating the diffractive contribution is given and is used to determine optimum mirror designs. Shaped mirrors and mirrors having amplitude and phase reflectivity tapers are studied. The concept of equivalent Fresnel zones is used to gain physical insight into the mode properties. 相似文献
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Although there has been a sustained interest in unstable open resonators for high-power laser applications, no satisfactory theory has previously been developed to explain the intricate behavior of the complex eigenvalues obtained by numerical solution of the resonator integral equation. The present study proposes a remarkably simple model that predicts the basic features of the published results. In this model, a two-dimensional resonator with finite convex mirrors is regarded as an open-ended waveguide with hyperbolic boundaries. Through use of the modal fields in the waveguide region and modal reflection and coupling coefficients due to the open end, one may construct a resonance equation for the eigenvalues of the free resonant fields (eigenmodes) in the unstable resonator. From a study of the resonance equation as a function of mirror size, it may be concluded that a single waveguide mode is primarily responsible for the eigenmode behavior near a loss minimum, and that two selectively coupled waveguide modes provide the behavior in the intervals between loss minima. The selection of the appropriate waveguide modes is accomplished with the aid of a resonance chart for the simpler problem wherein mode coupling at the open waveguide end is omitted. Results are presented and compared with the earlier literature. 相似文献
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The complicated loss behaviour of eigenmodes in unstable open resonators formed by finite convex cylindrical mirrors is explained in terms of a remarkably simple model that treats the resonator as a waveguide in the transverse direction. It is shown that selective coupling between two appropriately chosen waveguide modes suffices to establish the eigenmode loss characteristics. 相似文献
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本文使用一组辅助参量,在几何光学近似下,得到了一般多元件非稳腔的热不敏感条件及热敏感程度,并对其进行了详细的分析与讨论。 相似文献
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Waveguide laser resonators with a tilted mirror 总被引:1,自引:0,他引:1
We present a multimode theory of square-bore waveguide laser resonators with one well-aligned and one tilted plane mirror. Our theoretical results for mode content, resonator loss, and power output agree reasonably well with experimental results from an RF-excited CO2 laser with a376 times 1.5 times 1.5 mm Al/Al2 O3 waveguide. The mode propagation coefficients of this structure are discussed. We model a diffraction grating as a plane mirror with a wavelength-dependent tilt, and conclude that previous single-mode theory has underestimated the severity of the line-hopping constraint on tunable waveguide CO2 laser performance. 相似文献
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