Description of the project. Efficient Chip-Integrated Photon Counting Detectors

我们提出了一种新型的光电探测器的基础上多路复用芯片集成的倏逝耦合超导薄膜。这种方法可以实现高达数百个光子的单光子分辨率-比当前设备提高了百倍。在EPSRC的资助下，我们的团队与Peter Smith（ORC，南安普顿）和Sae Woo Nam（NIST Boulder）的团队合作开发了渐逝耦合光子计数探测器。其概念是硅基二氧化硅波导制造得足够靠近芯片表面，以便沉积在表面上的薄金属膜吸收导模的渐逝场。在这里，我们利用这种探测器设计的一个独特方面：未被探测器吸收的光保持在引导模式中。因此，倏逝波耦合实现了将一系列许多检测元件链接在一起的高效、高度可扩展的方案。我们将开发具有两种类型元件的设备，这些元件在时序和数字分辨率方面提供互补性能：过渡边缘传感器（TES）和超导纳米线单光子探测器（SNSPD）。在隔离中，这些元素被一个（SNSPD）或几个（TES）光子饱和。有效的多路复用避免了元件饱和，同时检测到许多激发的总和。该项目的目标是提供第一个多路复用探测器与单光子分辨率扩展超过一百个光子。这项工作将包括设备建模，量子探测器层析成像的特性，以及对多路探测器极限的理论研究。该学生还将与NQIT光子学研究人员一起工作，以推进光子量子模拟器和基于纠缠的量子随机数发生器（QRNG）的应用。

We propose a new type of photodector based on multiplexed chip-integrated evanescently coupled superconducting films. This approach can achieve single-photon resolution up to hundreds of photons- a hundred-fold improvement over current devices. Our team developed evanescently coupled photon counting detectors in an EPSRC-funded collaboration with the groups of Peter Smith (ORC, Southampton) and Sae Woo Nam (NIST Boulder).The concept is that silica-on-silicon waveguides are fabricated sufficiently close to the chip surface so that thin metal films deposited on the surface absorb the evanescent field of the guided mode. Here, we leverage a unique aspect of this detector design: light that is not absorbed by a detector remains in the guided mode. The evanescent coupling therefore enables an efficient, highly scalable scheme that chains together a series of many detection elements. We will develop devices with two types of elements that provide complementary performance in timing and number resolution: transition edge sensors (TESs) and superconducting nanowire single-photon detectors (SNSPDs). In isolation, these elements are saturated with one (SNSPD) or a few (TES) photons. Effective multiplexing avoids element saturation while detecting many excitations in sum.This project aims to deliver the first multiplexed detector with single-photon resolution extending over a hundred photons. The work will include device modelling, characterisation by quantum detector tomography, and a theoretical study on the limits of multiplexed detectors. The student will also work alongside NQIT photonics researchers to progress application in photonic quantum simulators and an entanglement-based quantum random number generator (QRNG)