Maximising Shared Capability of the Ultrafast Spectroscopy Laser Laboratory at Sheffield

光与物质的相互作用是现代科学中最重要的领域之一。它支撑着可用于未来通信、计算、显示和照明设备的新兴光子材料技术；预计这一技术部门在中短期内的经济影响将非常大。光与物质的相互作用也是光合作用将阳光转化为能量的基础，是地球上生命的基础。自然光合作用是非常有效的：现在的目标是建立人工系统，模仿自然光合作用系统的关键特性，这样我们就可以最终收获阳光作为能源，并为人类长期可持续的能源生产做出重大贡献，这种能源生产不依赖化石燃料，也不污染环境。人工光收集的任务是广泛的：我们不仅需要构建能够有效捕获光的分子系统或材料，而且还需要能够利用它直接产生能量（例如，光伏电池中的电力），或者驱动化学反应，提供“储存的能量”作为太阳能燃料（例如，通过提供将废物二氧化碳转化为液体燃料的能量）。超快激光光谱学允许人们以许多不同的方式检查分子和材料在吸收光后发生了什么，既可以在吸收后立即发生，也可以在几年的时间尺度上发生。所有关于光与物质相互作用的研究——无论是为了理解自然，利用能量，还是建造新的光通信设备——都需要能够测量光被吸收后分子和材料中发生的极快变化。最初的变化发生在飞秒的时间尺度上，可能涉及电子密度的运动，或者可以检测到的键振动的变化。在此之后，捕获的能量通过分子组装或材料“流动”，电荷或能量从一个地方移动到另一个地方——可以在皮秒到微秒的时间尺度上发生——可以再次详细地可视化。最后，任何随后可能在时间尺度上慢至毫秒的化学变化都将被可视化。其结果将是能够准确地监测当光子被吸收时材料和分子组合中发生了什么；当能量或电子随后穿过材料和/或导致结构变化时；当能量最终以各种方式使用时，从发光到引发化学反应。我们建立的实验室在英国大学系统中是独一无二的，因为它将超快光谱的各个方面结合在一个单一的集成设施中，这将使在单个地点使用单个样品进行全面的测量。它将涵盖广泛的时间尺度——从飞秒到毫秒，跨越11个数量级；从低能振动到高能电子跃迁的连续能量谱；还有各种各样的检测方法，可以探测到结构和电子特性的变化。这将为谢菲尔德和更广泛的英国科学界的研究人员提供最先进的方法来研究光与物质的相互作用。这个独特的设施使国家重要领域的广泛科学项目成为可能，并可能从技术发展（如更高效的照明）和利用阳光的更清洁、更便宜的能源生产中造福社会。由于我们所有的方法都是基于尖端技术，它们需要高度专业的科学家来确保设备发挥其全部潜力，帮助不同的科学家群体使用它来接触到技术和知识的最前沿。

The interaction of light with matter is one of the most important areas in modern science. It underpins the emerging technologies of photonics materials that can be used in the communications, computing, displays and lighting devices of the future; the economic impact of this technology sector in the short-to-medium term is predicted to be very large. Interaction of light with matter is also the basis of the conversion of sunlight into energy by photosynthesis and is fundamental to life on earth. Natural photosynthesis is remarkably effective: the goal now is build artificial systems that mimic the key properties of natural photosynthetic systems so that we can, finally, harvest sunlight as an energy source and make a major contribution to mankind's long-term sustainable energy generation that is not fossil-fuel dependent and is not polluting. The tasks of artificial light-harvesting are extensive: not only do we need to construct molecular systems or materials that can capture light effectively, but they need to be able to use it to either generate energy directly (e.g. as electricity in photovoltaic cells), or to drive chemical reactions that provide 'stored energy' as a solar fuel (e.g. by providing energy for conversion of the waste-product CO2 to liquid fuels).Ultrafast laser spectroscopy allows one to examine in many different ways what happens to molecules and materials after they absorb light, both immediately after absorption and on a timescale of years.All research in light/matter interactions - whether it is directed at understanding nature, harnessing energy, or constructing new optical communications devices - requires the ability to measure the extremely fast changes that occur in molecules and materials immediately after light is absorbed. The initial changes take place on a timescale of femtoseconds and may involve movement of electron density, or changes in bond vibrations, which can be detected. Subsequent to this the captured energy 'flows' through the molecular assembly or material, and this movement of charge or energy from place to place - which can occur on timescales from picoseconds to microseconds - can again be visualized in detail. Finally any subsequent chemical changes that may occur on timescales as slow as milliseconds will be visualized. The result will be the ability to monitor exactly what happens in materials and molecular assemblies when the photon of light is absorbed; as the energy or an electron subsequently moves through the material and/or results in structural changes; and as the energy is finally used in various ways from luminescence to triggering chemical reactions.The laboratory that we build is unique in the UK university system as it combines diverse aspects of ultrafast spectroscopy in a single, integrated facility which will enable the comprehensive set of measurements at a single site with a single sample. It will cover a wide range of timescales - from femtoseconds to milliseconds, which spans 11 orders of magnitude; a continuous spectrum of energies from low-energy vibrations to high-energy electronic transitions; and a wide range of detection methods that allow changes in structure and electronic properties to be probed. This will provide researchers both in Sheffield and the wider UK scientific community - with whom the facility is shared - access to state-of-the-art methods to studying light-matter interactions. This unique facility enables a wide range of science projects in areas of national importance and potentially benefit society from technological developments (such as more efficient lighting) and from cleaner, cheaper energy generation using sunlight.Since all our methods are based on cutting-edge technology, they require highly professional scientists to ensure that the equipment works to its full potential, to help diverse groups of scientists to use it to reach out to the very edge of technology and knowledge.