Revealing the high-redshift Universe with superconducting on-chip spectrometers

宇宙是如何开始的？第一个星系是什么时候形成的？什么是“暗能量”？这些是现代天文学和宇宙学中一些主要的悬而未决的问题。这些问题的答案都包含在物质的分布以及它在整个宇宙历史中的演变过程中。这项奖学金将开发一种新的传感器技术，这将使一种新的天体物理实验成为可能，这种实验将探测整个宇宙时间内结构的演变。当我们把望远镜对准夜空时，我们观察到来自数百万颗恒星和星系的光。因为光到达我们这里需要时间，所以我们实际上是在回顾过去，通过拍摄夜空的图像，我们能够建立起一幅宇宙进化过程中物质分布历史的图景。为了提取关于星系的所有信息，需要测量总亮度和光的颜色。摄谱仪能够将光分离成不同的颜色，是构建大型星系目录的关键工具。这些星系调查与宇宙微波背景（CMB）相结合，形成了我们目前对宇宙起源、内容和演化的理解。尽管有如此丰富的数据，但关于宇宙起源的直接证据和对暗能量的真正理解仍然难以捉摸。典型的星系调查是用光学/红外波段的强大望远镜进行的。这种波长的选择非常适合附近的星系，只在晚些时候探测，而早期的宇宙相对未被发现。宇宙的膨胀改变了从非常遥远的星系发出的光，并将波长延伸到亚毫米（亚毫米）波长范围。这种微弱的亚毫米光的检测提出了许多挑战，需要一种与传统半导体阵列完全不同的检测技术。虽然亚毫米单色相机有成熟的解决方案，但亚毫米光谱技术是一个需要专门开发的领域。目前最先进的仪器体积庞大，价格昂贵，通常需要移动部件，很难按比例缩放。这项奖学金的主要技术目标将是开发一种新技术，提供一种小型化、低成本的解决方案，利用成熟的技术。这项技术的关键是将精细调谐的超导集成电路组合在一块硅片上。用光刻技术定义超导电路，整个光谱仪可以在一平方厘米的硅上实现；这种功能以前需要一个接近一米大小的仪器。尺寸和成本的显著减少将使数千个光谱仪的二维阵列的构建成为可能，并且基于从最初的概念验证设备中获得的传统和经验，该研究将开发，演示和优化能够在整个亚毫米波长范围内工作的可扩展片上超导光谱仪。在墨西哥50米大型毫米望远镜上进行的专门演示为促进这项新技术的成熟提供了一个独特的机会，成功将开辟一个新的星系调查类别，以我们宇宙中最早的星系为目标，补充现有的光学/红外星系调查。事实上，这些技术的结合将成为重要的系统交叉检查，而调查之间的相互关联有望成为进一步改善宇宙学参数约束的有力方法。

How did the Universe begin? When did the first galaxies form? What is "dark energy"? These are some of the major outstanding questions in modern astronomy and cosmology. The answers to these questions are encoded in the distribution of matter and how it has evolved throughout the history of the Universe. This fellowship will develop a novel sensor technology that will enable a new class of astrophysical experiments that will probe of the evolution of structure throughout cosmic time.When we point our telescopes toward the night sky, we observe light that originates from millions of stars and galaxies. Because light takes time to travel to us, we are effectively looking back in time, and by taking images of the night sky we are able to build up a picture of the history of distribution of matter as the Universe evolved. To extract all the information about a galaxy, a measure of the total brightness and the colour of the light is needed. Spectrographs are able to separate light into colours, and are a key tool that can be used to construct large catalogues of galaxies. These galaxy surveys, in combination with the cosmic microwave background (CMB), have shaped our current understanding of the origin, content, and evolution of the Universe. Despite this wealth of data, direct evidence of how our Universe began and a true understanding of dark energy remain elusive. Typical galaxy surveys are built using powerful telescopes that operate at optical/infrared wavelengths. This choice of wavelength is well suited to nearby galaxies, probing only late times whilst leaving the early Universe relatively undiscovered. The expansion of the Universe modifies the light emitted from very distant galaxies and stretches the wavelength into the sub-millimetre (sub-mm) wavelength range. Detection of this faint sub-mm light poses a number of challenges and requires a fundamentally different detection technology to traditional semiconductor arrays. While mature solutions exist for sub-mm single-colour cameras, technology for sub-mm spectroscopy is an area requiring dedicated development. Current state-of-the art instruments are bulky and expensive, often requiring moving parts that are challenging to scale. The main technical objective of this fellowship will be to develop a novel technology that provides a miniaturised, low-cost solution that takes advantage of well-established techniques. The key to this technology is a combination of finely tuned superconducting integrated circuits deposited on a single silicon wafer. With superconducting circuits defined lithographically, an entire spectrometer can be realised on a square centimetre of silicon; this functionality would previously have required an instrument close to a metre in size. The significant reduction in size and cost will enable the construction of 2D arrays with thousands of spectrometers, and building on the heritage and experience gained from initial proof-of-concept devices, this fellowship will develop, demonstrate, and optimise scalable on-chip superconducting spectrometers capable of operating over the entire sub-mm wavelength range. A dedicated demonstration at the Mexican 50-m Large Millimetre Telescope within this fellowship offers a unique opportunity to boost the maturity of this novel technology, and success would open up a new class of galaxy surveys that target the earliest galaxies in our Universe, complementing existing optical/infrared galaxy surveys. In fact, the combination of these techniques would serve as important systematic cross-checks, and cross-correlations between the surveys promise to be a powerful approach to further improve constraints on cosmological parameters.