CAREER: Light-matter interactions at the single emitter level: Precise control of plasmon-exciton coupling

当光与物质相互作用时，它的性质--例如颜色和能量--可以被彻底改变。操纵光的新技术将为当今一些最大的挑战提供更好的解决方案，从最大限度地提高将阳光转化为电力的效率到构建更快的计算机。该项目旨在利用纳米尺度的金属结构在量子极限控制光一次控制一个光粒子（或光子）。然而，关于这种纳米尺度的结构如何影响单个光子，仍然存在许多问题。因此，该项目的第一个目标是开发新的显微镜方法，以前所未有的分辨率研究这些金属结构附近的光-物质相互作用。有了这个新发现的理解，第二个目标是使用纳米粒子构建量子计算机的第一步，这有望在未来的计算机中实现功率和速度的爆炸。该项目还有一个广泛的目标，即为所有学生创造茁壮成长的空间，不分性别、种族和社会经济背景。实现这一目标的部分办法是将伦斯勒妇女参与物理小组的外联活动范围扩大到当地的小学和中学，并将多样性教育纳入物理课程。量子信息科学的潜力正在推动对设计和生成新量子比特和设备（如晶体管）的需求，这些设备在单粒子水平上运行。金属纳米颗粒中的局部表面等离子体共振提供了将电磁场限制在远低于光的衍射极限的尺度的能力，并承诺了在量子水平上操作的可集成设备的可能性。特别地，这些等离子体共振可以与分子或半导体激子强烈耦合以形成新的杂化态。这些状态可用于开发单光子晶体管和其他功能量子电路的构建模块。然而，到目前为止，一些障碍限制了等离子体激元的实际应用。实际上，尽管等离子体模式呈现出非常强地耦合到物质的优点，但是等离子体腔中非常小的模式体积使得难以获得与诸如量子点的单个发射器的良好空间重叠。该研究项目提出设计，开发和表征新方法，用于单量子发射器和等离子体纳米腔之间耦合的基础研究和精确控制。研究目标包括：（1）开发一种新的工具，利用单分子超分辨率显微镜在实验上测量局域态密度，并了解等离子体纳米结构附近的光-物质相互作用，而不仅仅是从结构设计的模拟中了解到的;（2）利用等离子体光学捕获实现单个量子发射器与等离子体纳米腔之间的可再现和可控耦合;（3）在真实的时间内研究从弱耦合到强耦合的转变，并使用强耦合系统演示单光子封锁。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

When light interacts with matter, its properties – color and energy, for example – can be drastically modified. New techniques for manipulating light will enable better solutions to some of today’s biggest challenges, from maximizing efficiency in transforming sunlight into electricity to building faster computers. This project aims to control light at the quantum limit—one particle of light (or photon) at a time—using nanometer-scale metal structures. However, many questions remain about how such nanometer-scale structures affect individual photons. Thus, the first goal of this project is to develop new microscopy methods that will permit the study of light-matter interactions near these metal structures with unprecedented resolution. With this newfound understanding, the second goal is to use the nano-particles to construct the first step towards a quantum computer, which promises an explosion of power and speed in the computers of the future. This project also has broad goals to create space for all students to thrive, regardless of gender, race, and socioeconomic background. This will be achieved, in part, by expanding the scope of the Rensselaer Women in Physics group’s outreach activities to the local elementary and middle schools, and by incorporating diversity education into the physics curriculum. The potential of quantum information science is fueling demand for the design and generation of new qubits and devices, such as transistors, operating at the single-particle level. Localized surface plasmon resonances in metal nano-particles offer the ability to confine the electromagnetic field to scales well below the diffraction limit of light, and promise the possibility of integratable devices operating at the quantum level. In particular, these plasmon resonances can strongly couple with molecular or semiconductor excitons to form new hybridized states. These states can be used to develop single-photon transistors and other building blocks of a functioning quantum circuit. However, several roadblocks have up to now limited plasmons’ practical use. Indeed, although plasmonic modes present the advantage of coupling very strongly to matter, the very small mode volume in plasmonic cavities makes it difficult to get good spatial overlap with single emitters such as quantum dots. This research project proposes to design, develop, and characterize new methods for the fundamental investigation and precise control of the coupling between single quantum emitters and plasmonic nano-cavities. The research objectives include: (1) Developing a new tool to experimentally measure the local density of states using single-molecule super-resolution microscopy, and to understand light-matter interactions in the vicinity of plasmonic nano-structures, beyond what can be learned from simulations of the structure design; (2) Achieving reproducible and controllable coupling between individual quantum emitters and a plasmonic nano-cavity using plasmonic optical trapping; (3) Studying the transition from weak to strong coupling regime in real time and using the strongly coupled system to demonstrate single photon blockade.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.