Witnessing the birth of a crystal nucleus by non-photochemical laser-induced nucleation

晶体在自然界中无处不在，是科技领域无声的英雄：晶体构成了电子设备（如硅片）和药品（在药品中）的基础。晶体从熔融液体或溶液中最初形成称为成核。很难说在成核之前和期间发生了什么事件，因为它在地点和时间上是随机发生的。如果我们能够选择成核发生的时间和地点，我们就可以见证单晶的诞生。我们项目的目的就是利用一种叫做非光化学激光诱导成核（NPLIN）的新效应来做到这一点。这种效应使用激光发出的短脉冲光（十亿分之一秒）来刺激成核，我们最近开发了这种技术来选择发生的地点和时间。我们的目标是详细研究NPLIN，以揭示核成核过程中原子核的结构和运动。我们还希望能够利用NPLIN，这样它就可以合成和确定新材料的结构，比如蛋白质和药物。为了实现这些目标，我们将在英国中央激光设施建造一个独特的显微镜（激光散射显微镜），我们将使用两束激光，一束用于启动，一束用于观察晶体成核的过程。我们将用来观察晶体成核的激光也将使我们能够测量材料团簇的大小和运动，有些小到100纳米（一米的十亿分之一！），还没有准备好成核。我们还将能够用我们的光束（使用一种称为微拉曼光谱的技术）激发这些团簇和核，以找出这些团簇结构的细节以及它们在成核时如何变化。我们的仪器将使用由光制成的镊子（所谓的激光镊子）来捕获成熟的、有成核潜力的材料簇，我们将用强烈的光脉冲使这些被捕获的簇成核。通过我们的项目，我们将培养另一个重要的物种：下一代科学家之一，他们受过训练，装备精良，准备好利用国家一流的科学设施和未来的光源。该项目学生将学习使用最新的激光和光学技术来设计、建造和操作激光显微镜仪器。经过全面培训后，该学生将成为晶体成核技术方面的专家和科学前沿的创新者，致力于将英国置于全球技术经济的领先地位。

Crystals appear everywhere in nature and are the silent heroes of technology: crystals make up the foundations of electronic devices (e.g., silicon wafers) and pharmaceuticals (in medicines). The initial birth of a crystal, from a molten liquid or from solution is called nucleation. It is hard to say what the events are leading-up and during to nucleation, because it happens randomly in location and in time. If we were able to choose when and where nucleation took place, we could witness the birth of a single crystal. The aim of our project is to do just that, using a new effect called non-photochemical laser-induced nucleation (NPLIN). This effect uses a short pulse of light (billionths of a second) from a laser to stimulate nucleation, and we have recently developed this technique to choose where and when this happens. Our goal is to examine NPLIN in detail to unravel the structures and motions of nuclei that occur during nucleation. We also want to be able to harness NPLIN so that it can enable synthesis and determination of the structures of new materials, such as proteins and drugs. To achieve these goals, we will build a unique microscope (a laser scattering microscope) at the UK Central Laser Facility, and we will use two beams of laser light, one to initiate and one to watch crystal nucleation as it happens. The laser light we will use to watch crystal nucleation will also allow us to measure the sizes and movements of clusters of material, some as small as 100 nm (100 billionths of a metre!) that are not ready to nucleate. We will also be able to excite these clusters and nuclei with our beam (using a technique called micro-Raman spectroscopy) to find out details of the structure of these clusters and how they change as they nucleate. Our instrument will use tweezers made of light (so-called laser tweezers ) to trap clusters of material that are ripe and have the potential to nucleate, and we will nucleate these trapped clusters with an intense pulse of light. Through our project we will be nucleating growth of another important species: one of the next generation of scientists who are trained, equipped and ready to exploit the premier national science facilities and the light sources of the future. The project student will be trained in designing, building and operating laser microscopy instruments using the latest advances in lasers and optical technology. When fully trained, this student will be an expert in crystal nucleation technology and an innovator at the forefront of science, working to position the UK at the head of a global technological economy.