Manipulating light-matter interactions in bulk anisotropic metamaterials

非技术描述：光与物质以许多不同的方式相互作用，在我们的日常生活中可以观察到。这包括化学过程的散射、反射、折射、吸收或激发，例如人眼的视网膜视杆和视锥。特定光-物质相互作用的可能性和强度由所谓的选择规则决定。许多光-物质相互作用过程是被禁止的，或者更准确地说，是非常不可能的，因此限制了光学材料和工艺的基础研究和应用。操纵这些不太可能的相互作用的能力可能会增强许多领域的基础知识，包括原子、分子和光学物理、光子学、化学和纳米技术。这项研究的重点是开发新的纳米结构光学材料和结构，称为超材料，有助于产生特殊形状的光束。这些定制的光束使人们能够访问那些以前被禁止的光与物质的相互作用。除了其基础科学意义外，这项研究还可以应用于光谱学和传感设备、光伏系统和量子计算设备。这种实践经验，以及接触最先进的科学问题和他们的调查，帮助参与的学生为未来的科学和工程职业做好充分的准备。技术描述：原子和分子中的光谱跃迁在电偶极近似下是不允许的，但由于物质与辐射之间的相互作用中的高阶项而发生，称为禁止偶极。原子中的偶极禁忌光学跃迁构成了下一代原子钟的基础，以及用于量子信息处理器和量子模拟器的高保真量子比特的基础。然而，偶极-禁忌跃迁是非常弱的，因此呈现出窄的自然线宽。最近，人们认识到轨道角动量或涡旋光束可以使原子、分子和人造原子或纳米晶体发生对称性禁忌跃迁。然而，跃迁速率依赖于光束尺寸，并且随着涡旋光束尺寸的减小而增大。这项研究的目的是研究和论证利用轨道角动量载波束探测人造原子禁忌跃迁的可能性，这些光束已经利用强各向异性超材料结构退磁到亚波长尺度。轨道角动量束与原子的相互作用使中空束陷井成为可能，提高了受激辐射耗竭显微镜的空间分辨率，促进了量子信息处理。参与该项目的研究生和本科生获得了新型纳米结构材料的光谱学、纳米制造和光学表征方面的实践经验。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical description: Light interacts with matter in many different ways that can be observed in our everyday life. This includes scattering, reflection, refraction, absorption or excitation of chemical processes in, for example, retinal rods and cones of the human eye. The likelihood and strength of a particular light-matter interaction is governed by so-called selection rules. Many light-matter interaction processes are forbidden, or more precisely, highly-improbable, therefore limiting fundamental studies and applications of optical materials and processes. The ability to manipulate these improbable interactions is likely to enhance fundamental knowledge in many fields, including atomic, molecular and optical physics, photonics, chemistry, and nanotechnology. This research focuses on developing new nanostructured optical materials and structures, termed metamaterials, that help create specially shaped light beams. These custom-made light beams enable accessing those previously forbidden light-matter interactions. Beyond its fundamental science significance, this research could enable applications in spectroscopy and sensing devices, photovoltaic systems and quantum computing devices. This hands-on experience, along with exposure to state-of-the-art scientific problems and their investigations, helps thoroughly prepare participating students for future science and engineering careers. Technical description: Spectroscopic transitions in atoms and molecules that are not allowed within the electric-dipole approximation, but occur due to higher-order terms in the interaction between matter and radiation, are called dipole-forbidden. Dipole-forbidden optical transitions in atoms form the basis of next-generation atomic clocks, and of high-fidelity qubits used in quantum information processors and quantum simulators. However, dipole-forbidden transitions are very weak and therefore exhibit narrow natural linewidths. Recently, it was realized that orbital angular momentum, or vortex beams can make symmetry-forbidden transitions possible in atoms, molecules, and artificial atoms or nanocrystals. However, the transition rate depends on the beam size and increases when the vortex beam size decreases. The goal of the proposed research is to investigate and demonstrate the possibility of probing forbidden transitions in artificial atoms using orbital angular momentum carrying beams that have been demagnified to subwavelength scales using strongly anisotropic metamaterial structures. Interactions of orbital angular momentum beams with atoms enable hollow-beam traps, improve the spatial resolution of stimulated emission depletion microscopy and facilitate quantum information processing. Graduate and undergraduate students involved in this project gain hands-on experience in spectroscopy, nanofabrication and optical characterization of novel nanostructured materials.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.