CAREER: Interfacing trapped ions with telecom light

Denison University, Granville OH

Investigators

Abstract

Atomic physics experiments are making extraordinary advances in manipulating the quantum states of atoms, ions, and photons. Quantum control of these systems paves the way for new technologies such as quantum communication and quantum computing. This project will pioneer the use of lanthanum ions as a quantum bit in order to overcome some challenges for quantum communication networks. In particular, the project seeks to demonstrate an interface between ions and infrared photons. Since infrared light suffers minimal losses in an optical fiber, this approach can extend the size and efficiency of quantum communication networks. Students working on this project will benefit from atomic physics research training using lasers, optics, photonics, and fiber technology. The project will also develop new curricula incorporating quantum information science and photonics technologies. These activities will help prepare the next generation of STEM researchers, educators, and innovators. The research aim of this project is to establish doubly-ionized lanthanum as a quantum bit, or qubit, that can be controlled with telecom-compatible infrared light. Trapped atomic ions are one of the leading platforms for quantum information processing applications due to their long trapping times, good coherence properties, and the availability of methods to precisely control their quantum states using radiation. However, the established ion trapping experiments use ions from elements that mainly interact with visible and ultraviolet light. This poses a challenge for quantum networking because these wavelengths get attenuated in optical fibers. Doubly-ionized lanthanum is unique because telecom-compatible infrared light is all that should be needed for laser cooling and qubit operations. This project will use telecom-compatible infrared light first for Doppler cooling, and then for manipulation of qubits based on magnetic-field-insensitive hyperfine states. This is expected to be advantageous for long-distance quantum communication protocols that use atom-photon entanglement and for distributed quantum computation schemes. Directly interfacing ions with infrared wavelengths will also reduce the complexity of the system, and may thus enhance the potential for scaling up larger quantum networks. 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.