Fundamental Quantum Optics in Hollow-Core Photonic Crystal Fibers

该项目研究量子物理学的一个方面，即在最基本的层面上研究自然世界。几十年来，对光子（光的组成部分）或电子（原子的组成部分）等基本物体的实验导致了许多新技术，包括计算机和激光。下一代技术（称为量子技术）可能会创造出确保互联网上信息完美安全的方法，以及能够解决使用当今硬件无法解决的问题的计算机。光作为信息的载体，在这些技术中发挥着重要作用，因此越来越精细地控制光的能力对于未来的成功至关重要。本研究解决了在某些物质或材料中发生的所谓的光的非线性相互作用。例如，当某种颜色的非常强烈的光通过一根长的固体玻璃纤维时，可以通过非线性相互作用产生新的颜色。这种颜色变化的相互作用在科学研究和技术应用中都有许多用途。然而，存在一个问题，称为“拉曼散射”，这导致除了那些期望的颜色之外，还产生许多不想要的颜色。 在这种类型的散射中，能量沉积在构成介质的分子的振动中。这些不需要的、随机产生的颜色会降低光的纯度，因此避免它们产生的方法是一个重要的目标。目前的研究正在开发这样一种手段，通过取代固体玻璃纤维与中空玻璃纤维充满氙气在极高的压力。因为氙是一种“惰性气体”，它不形成分子，因此不存在拉曼光散射机制。光学物理与光基信息科学（光子学）提供了一个将研究与科学教育结合起来的绝佳机会。从更技术的角度来看，该项目解决了量子光学研究的需要，以获得理想的相互作用来产生和操纵光的量子力学状态，包括单光子，纠缠光子，压缩态和纠缠态，以及用于执行量子门操作和实现量子通信方法。为了实现这些目标，本实验项目研究了使用高密度氙气原子限制在空芯光子晶体光纤（HC-PCF）的光参量过程。这样的介质将开启对基本量子光学过程的研究，而不存在通常有害的拉曼散射。消除拉曼散射消除了单光子源中的自发光子发射背景信号，并消除了光孤子传播中的拉曼诱导频移，这限制了可以实现的量子噪声压缩的程度。它还减少了泵浦激光器的退化。这样的系统可以为量子信息方案带来良好控制的非线性光学过程。开发操纵和控制量子系统状态的方法在科学和量子信息技术、计量学、量子化学、纳米力学等领域具有广泛的兴趣。该主题将量子光学家与光学器件科学家和材料科学家聚集在一起。

This project studies an aspect of quantum physics, which is the study of the natural world at its most fundamental level. Experiments with elementary objects such as photons (constituents of light) or electrons (constituents of atoms) has led over the decades to many new technologies, including computers and lasers. The next generation of technology (called quantum technology), might create the means for ensuring perfect security of information on the internet, as well as computers that can solve problems unsolvable using today's hardware. Light, as a carrier of information, plays important roles in such technologies, so the ability to control light more and more finely is crucial for future success. The present study addresses the so-called nonlinear interactions of light that occurs in some substances or materials. For example, when very intense light of a certain color travels through a long solid-glass fiber, new colors can be created by nonlinear interactions. Such color-changing interactions have many uses, both in scientific research and in technological applications. A problem exists though, called "Raman scattering," which leads to the production of many unwanted colors in addition to those desired. In this type of scattering, energy is deposited in the vibrations of molecules making up the medium. These unwanted, randomly produced colors can degrade the purity of the light, so a means to avoid their production is an important goal. The present study is developing such a means by replacing solid-glass fibers with hollow glass fibers filled with xenon gas at extremely high pressure. Because xenon is a "noble gas" it does not form molecules, and so the Raman light scattering mechanism is absent. Optical physics and light-based information science (photonics) offer excellent opportunities to integrate research with science education.From a more technical perspective, the project addresses the need in quantum optics research for attaining ideal interactions for generating and manipulating quantum-mechanical states of light, including single photons, entangled photons, squeezed states, and entangled states, as well as for performing quantum gate operations and implementing quantum communication methods. Toward these goals, this experimental project studies optical parametric processes using high-density atomic xenon gas confined in hollow-core photonic-crystal fibers (HC-PCF). Such a medium will open up the study of fundamental quantum optical processes without the often-deleterious presence of Raman scattering. Elimination of Raman scattering removes spontaneous photon emission background signals in single-photon sources, and removes Raman-induced frequency shifting in optical soliton propagation, which limits the degree of quantum noise squeezing that can be achieved. It also decreases pump-laser degradation. Such a system could lead to well-controlled nonlinear optical processes for quantum information schemes. Developing the means to manipulate and control the states of quantum systems is of broad interest in science and in quantum information technology, metrology, quantum chemistry, nano-mechanics, etc. The topic brings together quantum opticians with optical device scientists and material scientists.