Broadband optical quantum memories: From atomic vapors to solid-state systems

Jonas Becker - Imperial College London

Broadband optical quantum memories: From atomic vapors to solid-state systems

Photonic encoding of quantum information is key to the realization of scalable quantum technologies such as provably-secure quantum communication over long distances or interconnected local nodes of a distributed quantum processor. However, many of the tasks involved in these applications, such as single-photon-generation, photon-photon gates, and entanglement generation, rely on probabilistic processes, posing barriers to efficiency and scalability. Optical quantum memories, devices that can store and recall quantum states of light on demand, can overcome these limitations by synchronizing probabilistic processes as well as providing additional functionalities such as coherent filtering, temporal mode manipulation, and memory-enhanced photon-photon interactions.

In this seminar, I will discuss quantum memory protocols based on off-resonant two-photon interactions in lambda- and ladder-type atomic systems, originally developed in our group for alkaline vapor-based memories, and I will highlight recent results focusing on noise suppression and temporal mode selection and conversion using this platform. In the second part of this talk I will then show how these protocols can be adapted to solid-state systems and present recent work utilizing silicon vacancy centers in diamond as well as Pr3+:Y2SiO5, paving the way for scalable and potentially chip-integrable solid-state quantum memories with high bandwidths.