轨道角动量光束的光—声参量放大

发布时间：2018-06-08 01:20

本文选题：轨道角动量 + 受激布里渊散射　；参考：《哈尔滨理工大学》2017年硕士论文

【摘要】：轨道角动量(Orbital Angular Momentum,OAM)作为光子的一个自由度,因其特殊的力学效应和可构建一个完备的无限维Hilbert空间,在经典和量子等领域倍受人们关注,成为国际光学界研究热点之一。目前,基于OAM光束在微粒操纵、空间光通信、显微成像和量子信息等领域的应用已取得了显著成果,但是在产生和传输阶段能量不足是限制OAM光束发展的重要因素。因此,本文利用受激布里渊散射原理对OAM光束进行光-声参量放大(Light-Acoustic Parametric Amplification,LAPA),并进行理论分析和实验验证。首先,从OAM光束概念出发,分析了OAM光束的产生方法,并对螺旋相位板法产生的OAM进行推导。利用耦合波理论推导了OAM光-声参量放大模型。其次,基于LAPA理论模型,利用MATLAB软件模拟了泵浦光和信号光分别为不同Laguerre-Gaussian模式产生的声场,并对泵浦光、信号光、声波场三者之间的OAM守恒关系进行了验证。利用有限元分析原理对信号光在放大前和放大后的相位和空间强度分布进行了分析。最后,搭建了共线和非共线LAPA实验系统,验证了放大前后泵浦光、信号光和声波场三者之间的OAM守恒,并对放大后光场的强度分布、相位结构、和光-声耦合过程中的能量转换率进行了分析。在共线结构中,泵浦光能量Ep4mJ时,拓扑荷为1的OAM信号光经放大后能量转换率可达到40%,证明LAPA可实现对OAM信号低噪声、高增益放大,输出光信号的相位和强度分布与泵浦光无关。针对微弱信号共线放大噪声的影响,采用非共线放大装置实现对OAM微弱信号低噪声放大,在非共线夹角小于10mrad时,入射角度几乎不影响放大后OAM信号光的质量,非共线夹角?为10mrad时放大率最高可达到109以上,非共线结构更有利于微弱OAM信号光的放大和提取。
[Abstract]:As a degree of freedom of photons, orbital angular momentum (Orbital Angular momentum) has attracted much attention in classical and quantum fields because of its special mechanical effects and the ability to construct a complete infinite dimensional Hilbert space. At present, the applications of OAM beams in the fields of particle manipulation, space optical communication, microscopic imaging and quantum information have achieved remarkable results. However, the lack of energy is an important factor limiting the development of OAM beams in the stage of generation and propagation. Therefore, the stimulated Brillouin scattering principle is used to amplify the OAM beam by optoacoustic parametric amplification, and the theoretical analysis and experimental verification are carried out. Firstly, starting from the concept of OAM beam, the generation method of OAM beam is analyzed, and the OAM generated by spiral phase plate method is deduced. The optical-acoustic parametric amplification model of OAM is derived by using the coupled wave theory. Secondly, based on the LAPA theory model, the acoustic field produced by different Laguerre-Gaussian modes of pump light and signal light is simulated by MATLAB software, and the OAM conservation relationship among pump light, signal light and acoustic field is verified. The phase and spatial intensity distribution of signal light before and after amplification are analyzed by using the finite element analysis principle. Finally, a collinear and non-collinear LAPA experimental system is built to verify the OAM conservation of pump light, signal light and acoustic field before and after amplification, and the intensity distribution and phase structure of the amplified light field. The energy conversion rate in the process of photoacoustic coupling is analyzed. In the collinear structure, when the pump energy is Ep4mJ, the energy conversion rate of OAM signal with topological charge 1 can reach 40. It is proved that Lapa can amplify OAM signal with low noise and high gain. The phase and intensity distribution of the output signal is independent of the pump light. Aiming at the effect of collinear amplification noise of weak signal, a non-collinear amplifier is used to amplify the weak signal. When the angle of non-collinear angle is less than 10mrad, the incident angle can hardly affect the quality of the amplified signal, and the non-collinear angle? The maximum magnification of 10mrad is above 109, and the noncollinear structure is more advantageous to amplify and extract the weak 10mrad signal.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O43

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