Summary
In this project we develop a quantum interface between microwave and optical photons as a key enabling technology of a hybrid quantum network. In such a network, the robust optical photons carry quantum information through optical fibres over long distances, while superconducting microwave circuits protected from thermal photon noise by the low temperature environment of a dilution refrigerator function as quantum nodes, providing memory, processing and routing capability. Our work includes developing an integrated, microfabricated device that interfaces the fragile microwave photons and with optical photons through either individual or ensembles of three-level solid-state quantum emitters, such as nitrogen vacancy (NV) centers in diamonds. In addition, we are developing novel quantum memory and repeater designs. Here the device itself could serve as an optical quantum memory, storing information in the ground states where we may perform quantum control via a microwave circuit. It could also serve as a specialized quantum node. Entangling operations between remote superconducting circuits can be performed for repeater operation. Finally, we will also develop an efficient microwave photon detector that works by converting microwave photons into optical photons, which can then be efficiently detected with existing technology.

Figure 1. Microwave to optical conversion with a three level quantum emitter coupled to a microwave stripline cavity and an optical, e.g. a photonic-crystal, cavity: A microwave photon couples the two ground states |g> and |s> of a three-level quantum emitter with the help of the microwave cavity. The conversion is then completed through an optical pump and an enhanced emission into optical cavity coupled to the transition between the excited state |e> and the ground state |g>.
Related Content

Entangled States of Beams and their Applications
Summary With David Cory and collaborators at the National Institute of Standards and Technology (NIST) we explore how to engineer beams of neutron or photons that carry entanglement. The degrees of freedom that can be entangled include spin (polarization), momentum, displacement, and angular momentum. These have potential applications ranging from studies of helical internal magnetic fields […]
September 7, 2016

Quantum Sensing with Small Quantum Systems
Summary There are small quantum systems over which we have very good control and which have long lifetimes. Examples include the phosphorous (P) defect in silicon (Si) and the nitrogen vacancy (NV) defect in diamond. With P defect in Si, we focus on improving our understanding of the hyperpolarization mechanism to better enable engineering of […]
December 1, 2016

Photonic Quantum Processor
Photonic quantum processors based on integrated quantum photonic circuits require entangled photon pairs to perform quantum computations. However, current state-of-the-art technologies utilize probabilistic entangled photon sources with limited pair-extraction efficiencies, negatively affecting the computation speed. This project aims to boost the speed of on-chip quantum operations by using bright, on-demand entangled photon sources with an […]
April 24, 2023