Strongly Extended Superradiance in Diamond Meta-Materials

Harvard University, Cambridge MA

Investigators

Abstract

20th century technological applications of materials, such as semiconductors used in electronics and mechanical sensors, rely on a classical or semi-classical understanding of their properties. In more recent and emerging research, scientists and engineers seek to exploit the quantum properties of atoms, materials, and light to increase measurement sensitivity, advance communications technologies, and develop approaches to quantum computation that are scalable to large numbers. Interactions of light, or photons, with atoms serve as the foundation for quantum information and quantum computation experiments, and over time the fields of quantum information and nanoscale optics have merged together to demonstrate a variety of light-matter interactions. However, for most systems these interactions are limited to relatively small numbers of atoms and over small spatial extents relative to wavelengths of light. This project will combine the relatively large density of atoms in many tabletop atomic experiments with the scalability of quantum nanoscale platforms. The group has recently demonstrated a set of metamaterials, fabricated composite materials with exotic properties, with the special property of having zero refractive index at certain wavelengths. The research team will use its expertise in nanoscale optics to explore how the tunable properties of these materials can enhance atom-light interactions and open the door to new applications in quantum information processing and computing. The group collaborates closely with industry partners in order to efficiently transfer fundamental insights from academia into commercial applications. This project will contribute to the group's effort on education and outreach in two aspects: first, these novel metamaterials will be used as a platform in education to demonstrate the exotic material properties and interesting physical phenomena of metamaterials and quantum optics; second, this work will directly involve students at many different levels, providing hands-on research experience. Superradiance is a many-body phenomenon in which atoms radiate coherently with one another, and the effect of constructive interference leads to an N-fold increase in the spontaneous emission rate, where N is the number of atoms. The key requirement for this effect in most setups is that the atoms need to be within one wavelength from one another. If the atoms are not within a wavelength, the phase matching conditions for perfect coherence become increasingly complex in large systems with more than one dimension. Extended superradiance occurs when it is possible to obtain cooperative enhancement both in power and in decay rate in regions greater than a wavelength. Because of the lack of spatial phase advance in zero-index metamaterials, one can obtain perfect superradiance throughout space with low radiative loss in zero-index metamaterials. The group will use the metamaterial platform to achieve superradiance of many atoms in a highly extended two-dimensional sample. The project introduces a metamaterial platform that permits very large cooperative spontaneous emission enhancement and opens the door to potentially transformative applications to scalable quantum information processes. It will lay the groundwork for a wide range of applications in sub-linewidth microlasers, low-decoherence quantum information processes, and scalable quantum memories.