Creating an artificial optical material to filter single photon states for quantum technologies

这个令人兴奋的项目是开发一种新的方法，使用被称为超表面的人造材料来集成量子光学元件。成功的申请者将在一个包括物理学家和工程师在内的跨学科团队中工作，为新兴的量子光子技术设计、制造和表征新型光学设备。在项目期间，学生将在数值模拟、制造和量子技术方面获得宝贵的技能。特别是，该项目将致力于建立一种新型的基于拓扑亚曲面的干涉仪来操纵光子的模式。对于变形表面的实际实现，将使用二氧化硅和二氧化钛等介电材料。该干涉仪将用于演示双光子量子干涉，这种干涉会导致一对对相同的光子一起离开干涉仪，尽管光子之间没有相互作用。这种明显的相互作用--被称为洪-欧-曼德尔干涉--是线性光学量子计算和光子网络提议的核心。尽管近年来量子光学取得了辉煌的进展，但量子光网络仍然面临着许多挑战。一个关键的挑战是将复杂和笨重的光学元件缩小到小型化的集成光学设备，同时保持相同的功能或开发新的功能。亚表面在这一领域提供了一个令人兴奋的机会，已经成功地用于感测光的手性(左手)的平板透镜，现在正在通过实现多重纠缠量子态进入量子光学领域。在这个项目中，学生将建立一个基于亚表面的Hong-Ou-Mandel干涉仪，它将能够在超薄结构中控制这一重要的量子效应。这还将允许在控制和实施诸如偏振变化或相移等多种功能时有更高的自由度。此外，亚表面元素之间的耦合将使用新的拓扑效应，如边缘模式，以允许在远场光学成像中测量单光子的新方法。

This exciting project is to develop a new way of integrating quantum optic elements using artificial materials called metasurfaces. The successful applicant will work in an interdisciplinary team including physicists and engineers to design, fabricate and characterise novel optical devices for emerging quantum photonic technologies. The student will acquire valuable skills in numerical simulation, fabrication and quantum technologies during the project. In particular, this project will focus on building a new type of interferometer based on topological metasurfaces to manipulate the modes of photons. For practical implementations of the metasurfaces, dielectric materials such as Silica and Titanium Oxide will be used. This interferometer will be used to demonstrate the two-photon quantum interference, which causes pairs of identical photons to leave the interferometer together, despite the fact there is no interaction between photons. This apparent interaction - termed Hong-Ou-Mandel interference is at the heart of proposals for linear optical quantum computing and photonic networking. Despite the splendid advances in quantum optics in recent years, there remain many challenges for quantum optical networks. One key challenge is to scale down complex and bulky optical elements to miniaturised integrated optical devices while keeping the same functionalities or developing new ones. Metasurfaces present an exciting opportunity in this area, having already been successfully used in flat lenses sensing the chirality (handedness) of light and are now entering the field of quantum optics by realizing multiply entangled quantum states.In this project, the student will build a metasurface-based Hong-Ou-Mandel interferometer that will enable the control of this important quantum effect within an ultra-thin structure. This will also allow for a higher degree of freedom in controlling and implementing multiple functions such as polarization changes or phase shifts. Further, coupling between elements of the metasurface will use novel topological effects such as edge modes to allow new way of measuring single photons in far-field optical imaging.