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线、无线电和微波传感器观察太空时，我们看到的光不到银河系的一半。这种“丢失”的光大部分位于太赫兹（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“看不见”的气体以及恒星之间“黑暗”的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。尽管有着巨大的潜力，但现有的太赫兹传感器系统对于实验室以外的大多数应用来说过于庞大、脆弱和复杂，并且缺乏研究反应气体所需的灵敏度。此外，这种技术准备的缺乏限制了太赫兹系统在太空中部署的前景。英国可以在很短的时间内投资于关键THz组件和传感技术的真实演示，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。在这个奖学金项目中，我将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。量子级联激光器是一种高度紧凑的太赫兹辐射源，其功率是任何类似尺寸设备的1000倍以上。我已经建立了新的项目合作伙伴关系，以利用极快且稳定的TeraFET探测器，从而能够真实的实时测量气体浓度的微小变化。与以前的基于太赫兹量子化学的气体传感方案不同，我正在开发高精度的分析化学技术，并开发了第一个定制的多通道气室，其中太赫兹辐射反复穿过所研究的气体，估计灵敏度提高了100倍。我将调整我的国际领先的太赫兹气体传感仪器，使用紫外线（UV）激光来模拟高层大气中气体的行为，并在精确的时间“触发”化学反应。这将使我能够研究甲醛等挥发性有机化合物（VOC）在大气中反应的行为，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，我将提供真实的时间内研究工业和农业污染物浓度的方法，我将研究紫外泵浦/太赫兹探测“步进扫描”检测技术的潜力，以探测微秒时间尺度上高层大气反应的动力学。通过与RAL Space的合作，我已经展示了世界上第一个将太赫兹QCL与精密微机械波导集成在一起，天线和“片上”稳定子系统。这一更新阶段将通过在“方糖”大小的卫星兼容模块内使用集成功率和频率控制系统，开发第一个卫星兼容的太赫兹激光稳定方案，从而进一步改变能力。我将与RAL Space和TK Instruments合作，在卫星测试“试验板”上，在符合空间要求的制冷机中展示这种能力，包括定制的THz光学器件和校准目标，为未来在卫星平台上的部署奠定基础。为了维持我的研究愿景，并将THz传感作为大气和空间研究的关键工具，我将与我的项目合作伙伴密切合作，以确保THz化学，地球观测和关键卫星有效载荷仪器的后续资金。我将为在轨部署和商业化制定路线图，包括通过地球探索者计划为欧洲航天局卫星使命开发科学和技术案例。