局域体全息光栅的衍射性质及集成化光学器件的研究
文献类型：学位论文
| 作者 | 闫爱民 |
| 学位类别 | 博士 |
| 答辩日期 | 2004 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 刘立人 |
| 关键词 | 局域体全息 祸合波理论 衍射效率 光束质量 体全息透镜 |
| 其他题名 | Diffraction Properties of Finite Size Volume Holographic Gratings and Their applications in Integrated Optical Devices |
| 中文摘要 | 随着现代科学技术的迅猛发展，光纤通信、空间激光通信、微小化卫星等信息光学领域都需要使用并发展小型的可集成化的光学元件。体全息光学元件作为信息光学处理系统的重要组成部分，如何充分利用其高速、并行、无交叉干扰等优点，发展自由空间传输的小型化和全光化的三维光学系统，已经成为光学器件及系统集成的发展方向和国际上的研究热点。我们课题组一直从事衍射光学的性质、空间局域光折变体全息记录和固定方法、局域体全息三维光学系统微集成等方面的研究。本论文旨在研究和讨论局域全息体光栅的衍射性质，探索局域体全息在集成光学器件方面的应用。主要内容包括：（1）研究了光束偏振对两维局域体全息光栅的衍射性质的影响。根据两光束的祸合波理论模型，对于任意偏振光入射到由交叉光束干涉形成的局域体全息光栅的情况，给出了透射波和衍射波振幅的解析式。讨论了记录过程和再现过程中入射光的偏振角对透射和衍射波振幅、衍射效率以及光束质量产生的影响。这些讨论对于补充和完善局域体全息理论，以及基于局域体全息的偏振光学元件的分析有重要意义。（2）研究了局域体光栅的光束质量（或保真度）的评价和优化方法。结合互相关函数的含义，给出了评价局域体光栅出射光束的光束质量优劣的函数，并给出了计算实例。为直观、准确地评价体全息光学元件甚至整个光学系统的光学质量提供了一个很好的手段。针对局域体全息光栅的高衍射效率产生的出射光束的光束质量差的矛盾，提出了一种光束质量优化的方法。通过让折射率调制振幅以适当的函数关系变化的方法，得到了近似理想的衍射振幅。研究结果对于扩束器、分束器、波导干涉仪等集成光学器件设计和分析非常有用。（3）研究了单轴晶体中的光折变体全息光栅的布拉格衍射性质。对于光轴方向任意的LiNbO3晶体中的无限边界体光栅，讨论了光轴方向对四种不同布拉格衍射的衍射效率的影响，给出了衍射效率最大时光轴的取向。对于光折变晶体中的局域体全息光栅，在光轴方向垂直于入射波矢和光栅矢量时，研究了它的寻常光到非常光（OE型）的各向异性布拉格衍射性质。在满足布拉格位相匹配条件和折射率调制张量的非对角元素不为零的条件时，OE型各向异性衍射可以发生，并且用双掺杂LiNbO3晶体进行了实验验证。在此基础上，用两维祸合波理论给出了衍射振幅的解析表达式，计算了光栅的衍射效率。结果表明，对于OE型布拉格衍射，局域体光栅有很好的角度和波长选择性。研究结果对基于体光栅的全息光学器件的优化设计以及信号处理系统具有重要的指导意义。（4）为了使光学系统更加紧凑化和稳定化，文中提出了一种平板光学器件一光折变平板透镜：它由光折变LiNbO3晶体平板和局域体全息光栅透镜两部分组成。该透镜由平面波和球面波在光折变晶体平板内干涉记录形成的，并用局域全光固定的方法来固定的。它可以对垂直入射晶体平板的平行光束实现横向传输并聚集，也可以对一束由点光源产生的发散球面波产生横向传输，并沿着垂直于平板准直输出。文中利用体全息的三维祸合波理论分析了这种光栅透镜的衍射性质和聚焦能力。这些理论分析为光折变平板透镜的进一步深入研究打下了很好的理论基础，对于研制高性能的平板光学元件具有十分重要的理论指导意义。本论文提出的光折变平板透镜，除了具有普通光学透镜的聚焦和准直的功能外，还具有体积小、重量轻、结构简单可靠、抗环境干扰能力强、平板结构易于微小化集成的优点。 |
| 英文摘要 | With the rapid development of modern scientific technology, some information optics fields such as fiber communication, space laser communication, optical information processing and minimizing satellites need to develop minimized and integrated optical components. Volume holographic optical component belongs to an important fraction of information optical processing system. And it preserves natural parallel, non-cross interaction and high speed interconnects properties. How to fully use its intrinsic virtues to develop a minimized and all-optical 3D optical system? It is thus an important direction of optical devices and their systems. In our research group, we devote ourselves to research the properties of diffraction optics, the recording and fixing technique of photorefractive local volume holograms, local photorefractive holograms and their 3D integration. In this dissertation, the diffraction properties of finite size volume holographic gratings and their applications in integrated optical devices are investigated. The details are listed in the following: (1) The influences of the polarization states on the diffraction properties of crossed-beam volume gratings are investigated, Simple analytical solutions for the amplitude profiles of the transmitted and diffracted waves are obtained. We discuss the influences of the polarized azimuths of the incident wave at both recording and reconstruction on the amplitude profiles of the transmitted and diffracted waves, diffraction efficiency and beam quality. These results are important for extending local volume holographic theory and providing a valuable means of analyzing volume holographic optical devices. (2) The evaluating function of the beam quality for crossed beam volume gratings is proposed, based on the definition of cross correlation function. It proves a valuable technique to evaluate intuitively and accurately the beam quality of local volume holographic component and even the whole optical system. Some references point out that high efficiency in volume grating may considerably distort the shape of the output beam. It is a trade-off between them. To solve the problem, a method for improving the beam quality of the crossed-beam volume gratings is suggested. We can obtain the almost desired profile of diffracted amplitude by changing the modulation depth of the refractive index. The analysis would be very valuable in integrated optics for beam expanders, beam splitters and for analyzing waveguide interferometers. (3) The properties of Bragg diffraction of light by photorefractive volume grating in axial crystals are investigated. For the case of infinite boundary volume gratings with an arbitrary optic-axis rientation, the influences of the optic axis on the diffraction efficiency of the four different Bragg diffractions have been shown.. The different orientations of the optic axis are also given when the respective diffraction efficiency reaches maximum. For the case of the crossed beam volume grating formed in photorefractive crystals, we discuss its properties of anisotropic diffraction which takes place in the plane orthogonal to the optic axis of the crystal and all wave vectors lie in that plane. It is demonstrated that the anisotropic diffraction can take place when the Bragg phase matching conditions are satisfied. And demonstrating experiment has been performed with double doped LiNbCb crystals. Based on two dimensional coupled wave theory, simple analytical expression for the amplitude profile of diffracted beam is obtained. Simulation calculations show that, for the ordinary to extraordinary (OE type) Bragg diffraction, the crossed-beam volume grating has the well wavelength and angular sensitivity. All the results are very useful for the optimum design of many holographic elements and signal processing system based on volume grating structures. (4) For enhanced compactness and stability of optical systems, a new device of photorefractive planar lens is presented, which is consisted of photorefractive LiNbO3 crystals slab and local volume holographic grating lens. It is recorded holographically by the perpendicular interference of a plane wave and a spherical wave in a photorefractive crystal slab. The local volume hologram is fixed by using of all-optical holographic fixing technique. The lens can laterally spread and focus the plane wave which vertically incident on the cystal slab, and vice versa. On the basis of the three-dimensional coupled-wave theory of volume holography, the diffraction properties, focusing ability and beam quality of the photorefractive planar lens are analyzed. These results can be used as a theoretic basis for further investigating photorefractive planar lenses, and also have important significance for achieving high performance planar optical devices. The lens designed in this dissertation, has the functiones of focusing or collimating that the conventional optical lens system possesses. Moreover, it has the particular properties of small space volume, light weight, simple and compact in construction, insensitive to environment disturbance, and easy of minimized integration. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15430]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 闫爱民. 局域体全息光栅的衍射性质及集成化光学器件的研究[D]. 中国科学院上海光学精密机械研究所. 2004. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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