Plasmon enhanced manipulation and sorting of nanoparticles

在过去的三十年里，我们对光与物质相互作用的理解发生了革命性的变化。激光的出现引发了许多主要的研究领域，其中之一就是用光捕获和操纵物质。光可以在微观尺度上移动透明物体。这是因为物体可能像一个小透镜，使光线弯曲并改变其动量。这使得粒子被保持在光场最亮的部分。光与物质相互作用的影响也发生在比原子体系更大的尺度上：阿什金的开创性工作导致了微观粒子（包括细胞等生物标本）的光学捕获的发展。这种规模的光学捕获已经在单分子生物物理学中引发了一场重大革命，因为它们提供了校准良好的力传感器，可以测量精确到飞牛顿的力。利用被困住的珠子作为锚来间接移动大分子，研究人员在我们对分子系统的理解方面取得了重大进展。虽然光学捕获在微观尺度上有很好的记录，但很少有人关注纳米级粒子的捕获和操纵。特别是在纳米尺度上的金属颗粒的捕获。这是一个高度热门和强有力的领域，未来的研究与光学陷阱。这项资助解决了这个问题，重点是使用等离子体共振来增强粒子的捕获：这种共振的发生是因为入射光与纳米金属粒子中的电子相互作用，导致这些电子振荡和辐射。这些振荡是被抑制的，但总的来说，它们会引起共振效应，对纳米颗粒的使用产生重大影响。这笔拨款将着眼于对这种捕获技术的深入研究，甚至着眼于纳米颗粒的分类。这项工作将扩展到量子点。总的来说，纳米粒子和量子点在成像、生物科学和广泛应用中的重要性意味着我们的研究将对各种学科产生重大影响。

The last thirty years have seen a revolution in our understanding of the light-matter interaction. The advent of the laser sparked numerous major research areas and one of these has been the trapping and manipulation of matter by light. Light can move transparent objects at the microscopic scale. This occurs as the object may act like a small lens and bend the light and change its momentum. This causes the particle to be held in the brightest part of the light field. The impact of the light matter interaction has also occurred on scales larger than that of the atomic regime: the pioneering work of Ashkin led to the development of optical trapping of microscopic particles including biological specimens such as cells. Optical trapping at this scale has led a major revolution in single molecule biophysics as they offer well calibrated force transducers that may measure forces right down to femtonewtons. Using trapped beads as anchors to indirectly move macromolecules, researchers have made major strides into our understanding of molecular systems.Whilst optical trapping at the microscopic scale is well documented, little attention has been paid to the trapping and manipulation of nanometric sized particles. In particular the trapping of metallic particles at the nanometer scale. This is a highly topical and powerful area for future studies with optical traps. This grant addresses this with the emphasis on using the plasmon resonance to enhance the trapping of particles: this resonance occurs because the incident light interacts with electrons in the nanometre metal particle causing these electrons to oscillate and radiate. These oscillations are damped but overall they cause a resonant effect that has major impact in the use of nanoparticles.This grant will look at an in depth study of this trapping techniques and even look at sorting of nanoparticles. The work will be extended to quantum dots. Overall the importance of nanoparticles and quantum dots in imaging, bioscience and wide ranging applications means our studies will have a major impact in a variety of disciplines.