Terahertz-frequency sensors for atmospheric chemistry and space research (renewal)

用于大气化学和空间研究的太赫兹频率传感器（更新）

• 批准号: MR/Y011775/1
• 负责人: Alexander Valavanis
• 金额: $ 75.42万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FY011775%2F1
• 关键词: Terahertz; frequency; sensors; atmospheric; chemistry

When we look into space with existing infrared, radio and microwave sensors, we see less than half the light in our galaxy. Most of this "missing" light lies in the terahertz (THz) or far-infrared part of the spectrum (1-10 THz, 30-300 micron wavelength). Indeed, the "invisible" gases in the Earth's atmosphere and the "dark" dust and gas clouds between stars all glow with distinctive THz fingerprints, providing a wealth of hidden information urgently needed by atmospheric and space scientists.Despite this great potential, existing THz sensor systems are too large, fragile and complex for most applications outside the laboratory and lack the sensitivity needed for studying reactive gases. Furthermore, this lack of technological readiness limits the prospects for THz systems being deployed in space. A short time-window is available for the UK to invest in real-world demonstrations of key THz components and sensing techniques and secure a place in forthcoming space missions, for example, via the ESA Earth Explorer 12 (or 13) programmes. Without this, the potential for a UK researcher to lead the world in this emerging area will be lost.In this fellowship, I am overcoming limitations of THz gas sensors by developing high-sensitivity systems based on quantum-cascade lasers (QCLs) - highly compact sources of THz radiation, which yield >1000 times the power of any similar-sized device. I have developed new project partnerships to exploit extremely fast and stable TeraFET detectors, enabling tiny changes in gas concentrations to be measured in real time. Unlike previous THz-QCL-based gas-sensing schemes, I am developing high-precision analytical chemistry techniques, and have developed the first custom-made multi-pass gas cell in which THz radiation passes repeatedly through the gas under study, yielding an estimated 100x improvement in sensitivity.In this Renewal phase of the fellowship, I will adapt my internationally-leading THz gas sensing instrumentation to use an ultraviolet (UV) laser to simulate the behaviour of gases in the upper atmosphere, and "trigger" chemical reactions at a precise time. This will allow me to study the behaviour of volatile organic compounds (VOCs) such as formaldehyde as they react in the atmosphere, and resolve the huge uncertainties in the effect of these reactions on climate change. By developing fast detection schemes, I will provide the means to study the concentrations of industrial and agricultural pollutants in real time, and I will investigate the potential for UV-pump/THz-probe "step-scan" detection technique to probe the dynamics of upper-atmospheric reactions on microsecond timescales.Through my partnership with RAL Space, I have demonstrated the world's first integration of THz QCLs with precision-micromachined waveguides, antennas, and "on-chip" stabilisation subsystems. This Renewal phase will provide a further step-change in capability, by developing the first satellite-compatible THz laser stabilisation schemes, through the use of integrated power and frequency control systems, within "sugarcube"-sized satellite-compatible modules. I will work with RAL Space, and TK Instruments to demonstrate this capability within a space-qualified cryocooler, including bespoke THz optics and calibration targets, on a satellite-test "breadboard", underpinning its future deployment on a satellite platform.To sustain my research vision, and establish THz sensing as a key tool for atmospheric and space research, I will work closely with my project partners to secure follow-on funding for THz chemistry, Earth observation and critical satellite payload instrumentation. I will produce a roadmap for in-orbit deployment, and commercialisation, including developing the science and technology case for a European Space Agency satellite mission through the Earth Explorer programme.

当我们用现有的红外、无线电和微波传感器观察太空时，我们看到的光还不到银河系的一半。大多数“缺失”的光位于太赫兹 (THz) 或光谱的远红外部分（1-10 THz，30-300 微米波长）。事实上，地球大气层中的“看不见”的气体以及恒星之间的“暗”尘埃和气体云都发出独特的太赫兹指纹，提供了大气和空间科学家迫切需要的大量隐藏信息。尽管潜力巨大，但现有的太赫兹对于实验室外的大多数应用来说，传感器系统太大、脆弱且复杂，并且缺乏研究反应气体所需的灵敏度。此外，技术准备不足限制了太赫兹系统在太空部署的前景。英国有一个较短的时间窗口来投资关键太赫兹组件和传感技术的现实世界演示，并在即将到来的太空任务中获得一席之地，例如通过欧空局地球探索者 12（或 13）计划。如果没有这一点，英国研究人员将失去在这个新兴领域引领世界的潜力。在这项奖学金中，我通过开发基于量子级联激光器（QCL）的高灵敏度系统来克服太赫兹气体传感器的局限性 - 高度紧凑型太赫兹辐射源，其功率是任何类似尺寸设备的 1000 倍以上。我开发了新的项目合作伙伴关系，以利用极快且稳定的 TeraFET 探测器，从而能够实时测量气体浓度的微小变化。与之前基于 THz-QCL 的气体传感方案不同，我正在开发高精度分析化学技术，并开发了第一个定制的多通道气体池，其中太赫兹辐射反复穿过所研究的气体，产生估计的灵敏度提高 100 倍。在该奖学金的更新阶段，我将调整我的国际领先的太赫兹气体传感仪器，以使用紫外线 (UV) 激光来模拟高层大气中的气体行为，并在一个精确的时间。这将使我能够研究甲醛等挥发性有机化合物（VOC）在大气中发生反应时的行为，并解决这些反应对气候变化影响的巨大不确定性。通过开发快速检测方案，我将提供实时研究工业和农业污染物浓度的方法，并且我将研究紫外线泵/太赫兹探头“步进扫描”检测技术探测污染物动态的潜力。通过与 RAL Space 的合作，我展示了世界上第一个将太赫兹 QCL 与精密微加工波导、天线和“片上”稳定子系统集成的技术。这一更新阶段将通过开发第一个与卫星兼容的太赫兹激光稳定方案，通过在“糖立方”大小的卫星兼容模块内使用集成功率和频率控制系统，提供进一步的能力改变。我将与 RAL Space 和 TK Instruments 合作，在卫星测试“面包板”上展示符合太空要求的制冷机（包括定制的太赫兹光学器件和校准目标）中的这种能力，支撑其未来在卫星平台上的部署。为了实现研究愿景，并将太赫兹传感确立为大气和空间研究的关键工具，我将与项目合作伙伴密切合作，确保为太赫兹化学、地球观测和关键卫星有效载荷仪器提供后续资金。我将制定在轨部署和商业化路线图，包括通过地球探索者计划为欧洲航天局卫星任务开发科学和技术案例。