CAREER: Dynamically Reconfigurable Cavity Quantum Electrodynamics with Solid-State Quantum Emitters

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Harnessing the quantum nature of light for more secure communication, faster computation, and more powerful sensing is on the horizon today following significant advances in quantum photonics in recent decades. A major outstanding challenge lies in designing interfaces between optical and matter-based quantum systems that can preserve fragile quantum states. Such interfaces are necessary for a wide variety of tasks, including generating light suitable for carrying quantum information, storing and retrieving photonic qubits, and mediating entangling operations between photons. Achieving these goals generally requires enhancing the strength of the light-atom interaction, which is naturally too weak for efficient quantum devices. A common method to enhance this interaction is to couple the atoms to an optical resonator or cavity, typically a precisely fabricated structure designed for a single application. The research proposed here aims to develop a dynamically reconfigurable platform for coupling atoms to an optical cavity by using highly coherent, cryogenically-cooled rare-earth atom dopants in a solid-state host that can be spectrally and spatially tailored to form the cavity mirrors and the coupled atomic ensemble. This flexible platform can be used for a variety of important applications, such as efficient and long-lived quantum memory for light, and can be incorporated into integrated optical devices. In addition, a new undergraduate research fellowship that targets students interested in quantum science and engineering from underrepresented backgrounds will be developed, with a focus on ensuring supportive mentorship that extends beyond the summer research experiences. Technical: The objective of the proposed work is to develop a dynamically reconfigurable cavity quantum electrodynamics system based on a spatially and spectrally tailored ensemble of highly coherent, cryogenically-cooled, rare-earth atom dopants in a solid-state host, which forms both the cavity mirrors and the coupled atoms. Rare-earth atoms in solids at cryogenic temperatures exhibit highly coherent atom-like behavior and an energy level structure that makes them suited to precise tailoring of their spatial and spectral profile via spectral hole-burning. A one-dimensional array of alternating spectral profiles acts as a highly reflective optical mirror. Furthermore, the presence of multiple metastable energy levels enables dynamic, optically controlled switching of the mirror between reflective and transmissive states via electromagnetically induced transparency. Additional spectral and spatial tailoring can enable more complex structures including optical cavities that can be coupled to each other and to ensembles of atoms. Thus a fully reconfigurable cavity quantum electrodynamics system is formed without any fabricated structures, with the additional feature of dynamically switchable cavity mirrors. This scheme will enable dramatic improvement in the efficiency of rare-earth ensemble-based optical quantum memory to store photonic qubits. Rare-earth atoms are already one of the most promising platforms for quantum memory and coupling a rare-earth ensemble to an optical cavity addresses outstanding challenges related to making compact devices with long storage times without sacrificing storage efficiency. And doing so in a way that is reconfigurable without the need to fabricate a cavity makes this a flexible platform for a wide variety of useful quantum devices. 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.