High-order orbital angular momentum modes in bright squeezed vacuum states of light

螺旋相位光束由于其携带的轨道角动量而吸引了越来越多的兴趣。的（几乎）无限的值导致不受限制的基态范围，即所谓的轨道角动量模式，这可以实现更大字母表的量子密钥分配，并提供抗窃听的高维量子信息。轨道角动量模式在远距离传输信息、设计新型成像系统和赋予量子密码学机会方面非常有前途。此外，轨道角动量模式可用于高分辨率和高灵敏度测量，并通过光-物质相互作用对粒子进行光学操纵。为了进一步提高轨道角动量模式的量子容量，可以使用每个模式具有巨大光子数的量子光。一个有希望的候选者是明亮的压缩真空。亮压缩真空是一种宏观的非经典光态，可以通过高增益参数下转换或四波混频获得，并且具有非常宽的光子数分布和非常高的光子数。与位移压缩光态不同，明亮压缩真空仅由量子噪声组成，并且具有强的光子数相关性，导致噪声降低到散粒噪声水平以下以及正交压缩。明亮压缩真空的这些特性使其在量子成像和灵敏度测量、量子光学力学、引力波探测、量子光非线性光学等方面具有广泛的应用前景。本论文的工作重点是对亮压缩真空中尚未探索的高阶轨道角动量模的物理性质进行理论描述，并对其进行制备和分类。所有用于制备和分选这种模式的方案都将基于使用附加光学元件和非高斯泵浦光束的两晶体和三晶体配置。将从施密特模式的观点来进行对所选择的轨道角动量模式的描述。提出了制备具有高正交压缩的单轨道角动量模和具有低于散粒噪声水平的噪声降低的光子数相关轨道角动量模对的方法。同时，我们计划建议和计算的计划，应用高阶轨道角动量模式的旋转的机械对象和通过强相关性从光子系统的机械，用于测试原子，分子，量子点的非对称吸收光谱，用于测试不同的对象的手征，和非常敏感的相位测量。此外，我们将发展包含时间序效应的明亮压缩真空中轨道角动量模的理论描述。

Helically-phased light beams attract more and more interest due to the orbital angular momentum that they carry. The (almost) unlimited value of leads to an unrestricted range of basis states, so-called orbital angular momentum modes, which may enable larger-alphabet quantum key distribution and provide high-dimensional quantum information resistant to eavesdropping. Orbital angular momentum modes are very promising for transmitting information over large distances, designing novel imaging systems and empowering quantum cryptography opportunities. Moreover, orbital angular momentum modes can be used in high-resolution and high-sensitivity measurements and for the optical manipulation of particles through light-matter interaction. To improve the quantum capacity of orbital angular momentum modes even further, one could use quantum light with huge photon numbers per mode. A promising candidate for that is the bright squeezed vacuum. Bright squeezed vacuum, is a macroscopic non-classical state of light that can be obtained via high-gain parametric-down-conversion or four-wave-mixing, and has a very broad photon-number distribution with very high photon numbers. Unlike displaced squeezed-light states, bright squeezed vacuum consists only of quantum noise and has strong photon-number correlations, leading to the reduction of noise below the shot-noise level as well as to quadrature squeezing. Such features of bright squeezed vacuum make it very attractive for various applications such as quantum imaging and sensitive metrology, quantum optomechanics, gravitational wave detecting, and nonlinear optics with quantum light. The proposed work focuses on the theoretical description of physical properties of so far unexplored high-order orbital angular momentum modes in bright squeezed vacuum, their preparation and sorting. All schemes for preparation and sorting of such modes will be based on the two- and three-crystal configuration with using an additional optical elements and non-Gaussian pump beams. The description of the selected orbital angular momentum modes will be performed from the point of view of Schmidt modes. The methods for preparation of a single orbital angular momentum mode with high quadrature squeezing and photon-number-correlated pairs of orbital angular momentum modes with noise reduction below the shot-noise level will be suggested. Simultaneously, we plan to suggest and calculate schemes of applying high-order orbital angular momentum modes for the rotation of mechanical objects and for passing strong correlations from the light subsystem to the mechanical one, for testing non-symmetrical absorption spectra of atoms, molecules, quantum dots, for testing the chirality of different objects, and for very sensitive phase measurements. Moreover, a theoretical description of orbital angular momentum modes in bright squeezed vacuum including time-ordering effects will be developed.