Efficient Matter-Based Broadband Photonic Quantum Memory

The ability to store particles of light is important for new methods of computing, communicating, and sensing based on quantum physics, which describes how things behave at the smallest scales. Making memories for light particles, or photons, that keep their properties remains a challenge. This is especially true for the very short pulses of light that are created in some of the most commonly used photon sources. This research will study how to build memories for such photons using atoms, explore ways to improve how long they can be stored, and study the quantum nature of the photons. The work will provide training to graduate and undergraduate students in quantum theory and experiment. The team will engage the greater population in quantum technology through the recently created Public Quantum Network that sends entangled photons to public spaces. New courses for a master’s program for high school teachers will also be developed to bring quantum physics to high school classrooms. This research will span fundamental theory, simulation, and experiment towards enhancing the resources for quantum processing through investigation of quantum memory operation in the GHz-THz bandwidth regime. Through this research an atomic-ensemble-based quantum memory platform will be extended to enable increased total efficiency, longer lifetime, and storage and retrieval of telecom-wavelength single photons. The memory will be applied to qubit storage and retrieval in the polarization, frequency, and spatial degrees of freedom, and frequency transduction. A recently developed theoretical model and experimental study of the quantum correlations inherent in Raman-based photon-pair generation will be extended to investigate Stokes-anti-Stokes photon-pair correlations, which determine the degree of quantum state purity of the produced single-photon states. By studying methods to enhance quantum memory operation, investigating its application in quantum information processing tasks, and elucidating and engineering its quantum correlations, this work will advance the broadly impactful goals of improved computation, communication, and sensing. 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.