QUantum-Enhanced SpecTroscopic molecular detection - QUEST

光学仪器对于识别物质和分子至关重要。分子物种的光谱检测为现代社会使用的大量关键技术和过程奠定了基础-从过程控制和制造、污染监测和控制、国土安全和医疗保健。由于这项技术的重要性，光谱检测仪器制造是一个数十亿英镑的全球行业，依赖于它们的加工价值高达数倍。判断探测器性能的两个关键指标是选择性(设备区分分子物种的程度)和灵敏度(确定在检测到目标物质之前必须存在多少物质)。这个项目将利用量子光来提高光谱分子检测的灵敏度和选择性。分子物种通常以微量存在，这使得它们的测量变得困难。这类仪器灵敏度的一个基本限制是传感器中使用的激光中存在噪声，这隐藏了光学信号强度中的非常显著的波动，从而能够检测非常微小的分子物种水平。在这个项目中，我们将通过利用量子光学中的最新进展--光的压缩量子态的应用--来解决这个问题。有了这种特殊形式的量子光，人们可以选择牺牲自己不感兴趣的光的特征知识，以获得自己想要的其他人的收益-在我们的项目中，我们可以最大限度地利用特征知识，从而提高光谱的精确度。这种方法最近在帮助下一代LIGO探测器在宇宙中更深处搜索引起引力波的天文事件的第一步中取得了成功，比2016年观察到的黑洞合并更深一个数量级。在这个项目中，我们将利用压缩光进行分子探测，具有前所未有的灵敏度，从而能够探测到比标准技术可能探测到的分子数量少得多的分子。我们将通过设计、构建和演示一个原型系统来实现这一点，该原型系统增强了最先进的干涉光谱分子检测技术。

Optical instruments are critical to identifying substances and molecules. The spectroscopic detection of molecular species underpins an enormous range of critical techniques and processes used in modern society - from process control and manufacture, pollution monitoring and control, homeland security, and healthcare. As a result of the importance of this technique, spectroscopic detection instrument manufacture is a multi-billion pound global industry, and processes worth many times that depend upon them. The two key metrics by which detector performance are judged are the selectivity (how well the device can distinguish one molecular species from another) and the sensitivity (determining how much of the substance of interest must be present before it can be detected). This project will harness quantum light to increase sensitivity and selectivity of spectroscopic molecular detection.Often, molecular species are present in minute amounts, making their measurement difficult. A fundamental limit to sensitivity of such instruments is the presence of noise in the laser light used in the sensor, which hides the very signature fluctuations in the optical signal intensity that enable detection of very minute levels of molecular species. In this project, we will address this by exploiting recent advances in quantum optics - the application of squeezed quantum states of light.With this special form of quantum light, one can choose to sacrifice knowledge of characteristics of the light that one is not interested in, in order to reap gains in others that one desires - in our project, we can maximise knowledge of characteristics that enable increased precision spectroscopy. Such an approach was recently successful in the first steps of helping the next generation of LIGO detectors to search an order of magnitude deeper into the universe for astronomical events causing gravitational waves, than the observed merging of black holes reprted in 2016.In this project, we will exploit squeezed light for molecular detection with unprecedented sensitivity, thereby enabling detection of far smaller amounts of molecules than are possible with standard techniques. We will achieve this by designing, constructing and demonstrating a protype system that augments state of the art interferometric spectroscopic molecular detection.