Arrays of on-chip microcavities for quantum applications

在不太遥远的未来，利用量子力学的设备将使计算、通信和传感系统的能力大大超过我们目前的技术。一个有希望的愿景是创造一个量子网络，或称“量子互联网”。在这样的网络中，光被用来在潜在的长距离上传输量子状态信息(通常使用低损耗光纤)，并且(在网络节点)使用原子或固态材料来处理和存储量子信息。量子技术发展面临的一个特别挑战是，光和物质之间的相互作用天生就很弱。在两面镜子(即所谓的光学腔体)之间放置原子或固态材料极大地提高了光-物质相互作用的效率，特别是在腔体尺寸达到微观尺寸的情况下。需要实用的工程解决方案来将纳米级固态材料嵌入到微米级的光学腔中，以及构建由大量这样的腔组成的系统。通常，这些系统还必须与电路集成。为实现这一目标而进行的世界范围内的研究工作正在进行中，但它仍然是一个重大的、尚未解决的技术挑战。这项拟议的工作是一项工程开发工作，源于我们在单个芯片上制造高质量、微型和开放访问的光学腔阵列的成熟和独特的能力。这些“开放”腔本质上是一对被空白空间隔开的超高反射率反射镜，这可能会将光和任意物质物体限制在相同的微观体积内。与大多数正在研究的替代技术相比，我们的工艺是独一无二的。此外，我们已经证明，这些腔在控制和定制嵌入式发射器的光发射方面具有巨大的潜力，并且它们非常适合将这种光耦合到外部光纤网络和从外部光纤网络耦合。在此基础上，我们提出了一个长期愿景，以实现结合微腔阵列的芯片，在这些腔内精确定位光发射器和机械谐振器的技术，以及用于调节和控制光的发射和吸收的芯片上的电线以及作为微波信号的接口。这可能导致迫切需要的量子构建块的实际和可扩展的实施，例如可控的单光粒子源(单光子发射器)和用于在光学和微波频率之间转换量子信息的设备(量子换能器)。这项工作承诺将使加拿大处于被广泛寻求的技术的前沿，并加强加拿大在量子信息科学领域本已强大的地位。

In the not-too-distant future, devices that exploit quantum mechanics will enable computing, communications, and sensing systems whose capabilities greatly exceed those of our current technologies.  One promising vision is the creation of a quantum network, or 'quantum internet'. In such a network, light is used to transmit quantum state information over potentially large distances (typically using low-loss fiber optics), and atoms or solid-state materials are used (at network nodes) to process and store this quantum information. One particular challenge for quantum technology development is that the interaction between light and matter is inherently weak. Placing atoms or solid-state materials between two mirrors (a so-called optical cavity) strongly increases the efficiency of light-matter interactions, especially as the cavity is scaled to microscopic dimensions. Practical engineering solutions are needed for embedding nano-scale solid-state materials into micro-scale optical cavities, and for building systems that comprise large numbers of such cavities. Typically, these systems must also be integrated with electrical circuitry. A world-wide research effort towards this goal is ongoing, but it remains as a significant, unsolved technological challenge. The proposed work is an engineering development effort, and springs from our established and unique capability to fabricate arrays of high-quality, microscopic and `open-access' optical cavities on a single chip. These `open-access' cavities are essentially a pair of ultra-high-reflectance mirrors separated by an empty space, which creates the potential to confine light and arbitrary material objects within the same microscopic volume. The monolithic (single chip) nature of our process is unique compared to most of the alternative technologies that are under study.  Furthermore, we have shown that these cavities have great potential for controlling and tailoring the emission of light for an embedded emitter, and that they are well-suited for coupling this light to and from an external fiber optic network. Building on this, we propose a long-term vision to implement chips combining arrays of micro-cavities, techniques for precisely locating light emitters and mechanical resonators within these cavities, and on-chip electrical wiring for tuning and controlling the emission and absorption of light and as an interface for microwave signals. This could lead to a practical and scalable implementation of critically needed quantum building blocks, such as controllable sources of single light particles (single photon emitters) and devices for converting quantum information between optical and microwave frequencies (quantum transducers). The work promises to place Canada at the forefront of widely sought technologies, and to enhance Canada's already strong standing in the field of quantum information sciences.