【作者】 王杰；

【导师】 石剑虹；

【作者基本信息】 上海交通大学 ， 光学， 2012， 硕士

【摘要】 早在1909年, Poynting就认识到了光子携带自旋角动量。直到1992年,光子携带的一种新形式的角动量-轨道角动量才被Leidon大学的Allen教授等人发现。由于光子的这种自旋自由度的特殊性质，人们可以实现对其量子比特的编码(qubit）；另一方面,光子轨道角动量在实现高维量子态的编码（qudits）方面有着重要的意义。2002年，光子轨道角动量分离技术被Glasgow大学的Padgett研究小组实验验证了，他们指出作为信息载体的轨道角动量，可大幅提高单个光子的通信容量。2001年有了一个巨大的新突破, Wien大学的Zeilinger研究小组实验验证了自发参量下转换条件下产生的光子具有轨道角动量纠缠的特性，从此,量子信息领域中轨道角动量展现出巨大的应用或者潜在应用前景。到目前为止，光子的角动量已在许多应用方面取得到了重要进展，包括冷原子操控，光学扳手，量子纠缠及量子信息处理,旋转Doppler效应等。总而言之，就目前的情况来看,光子角动量的研究仍然处于快速发展时期。其中量子纠缠（单光子纠缠和超纠缠）和量子纠缠在量子信息协议中的应用，以及角动量的非线性光学调控研究尚比较缺乏，特别地,高维量子特性的轨道角动量在量子信息领域中的应用还比较缺乏研究。目前，很多研究工作已经提出各种产生角动量的方法，本论文首次引入电光效应产生角动量，并系统研究了光在铌酸锂晶体中经过电压调制后，偏振态，光子自旋角动量和轨道角动量的特性。本论文的主要内容和创新点如下：我们以该理论为基础，研究了高斯光束在周期性极化铌酸锂中传播的特性，以及晶体输出端的输出光的轨道角动量分布，给出不同电压，不同束腰的高斯光束，以及不同的晶体长度对轨道角动量的影响，轨道角动量的这种变化，在粒子操纵领域有着重要的应用。基于螺旋极化的周期性极化铌酸锂，研究了在电光效应下，螺旋光输入时，输出光的偏振态演化。还研究了不同电压下，自旋角动量，轨道角动量，总自旋和总轨道角动量。全面了解这些性质，对于电光调制器的制作的改良和优化有一定的指导作用。通过这项研究，可以制作角动量开关和其他电光器件，以用于角动量传递、转换和角动量开关的制作。更多还原

【Abstract】 In 1909 Poynting realized that circularly polarized light has spin angular momentum However, the idea of orbital angular momentum (OAM) of light came much later. In 1992, Allen et al recognized that a light beam can carry OAM which is associated with its spiral phase front OAM allows for qudits while spin realizes only one qubit In 2002 a research group in Glasgow University suggested an interferometric method to distinguish single photons based on individual OAM which makes loading more information onto a 2001 is another breakthrough, and that demonstrated the photon pairs from pararnetric down-conversion showed high-dimensional OAM entanglement. Until now, photon angular momentum has many applications, ranging from manipulation of cooled atoms, optical spanner, rotational quantum communication and Doppler shift to quantum entanglement. However, the manipulation of photon angular momentum by means of nonlinear optics and its applications in quantum information protocols and quantum entanglement (including single-photon entanglement and hyperentanglement) are still rare In particular, the high-dimenional OAM has not been fully exploited in the field of quantum information yetMany researches have suggested many kinds of means to generate angular momentum. The OAM generated by using EO effect was initially advised in this paper. We systematically investigate the polarization, the spin angular momentum and the orbital angular momentum of output light under EO effect. The main results and points included in this paper are summarized as followsBased on the coupling theory, we study the characters of Gaussian beam propagating in PPLN and the OAM distribution of the output light. For different applied fields, beam waists, and crystal lengths, the OAM distribution on the transverse section changes. These results will play an important role in the area of manipulation.Under EO effect, light beams with spiral phase in HPPLN, coupled out of the crystal. The evolution of polarization of output beam is investigated. For different applied fields, SAM and OAM, total SAM and total OAM are also studied. All these special characters can help on making EO modulator. These natures of HPPLN may find applications in polarization state control and angular momentum switch.更多还原