Michal Bajcsy, Stanford University
Abstract
Physical systems in which linear and nonlinear light-matter and light-light interactions at few photon levels can be achieved and controlled have been a long standing focus of both science and engineering. The motivations for these efforts include studies of quantum-mechanical phenomena in condensed matter or atomic systems, quantum metrology, long distance secure communications and scalable quantum computers, as well as devices for high-speed and low power processing or transfer of information. Atomic and solid state quantum emitters coupled to optical resonators or photonic waveguides are considered excellent platforms for controllable implementation of these light-matter and light-light interactions at single or few photon level. Yet, while significant progress has been made in physical implementation of these systems during
recent years, scalability of both atomic and solid state platforms remains elusive. In my talk I will describe recent experiments that could potentially serve as stepping stones toward scalable on-chip architectures for quantum optics applications.
First, I will discuss our experiments in solid-state cavity quantum electrodynamics based on a single self-assembled InAs quantum dot embedded in a GaAs photonic-crystal cavity. With the quantum dot as a two-level quantum emitter and using the phenomena of photon blockade and photon-induced tunneling, we recently managed to probe the higher manifolds of the Jaynes-Cummings Hamiltonian [1]. Additionally, we used this coupled cavity-dot system to implement a proof-of-principle all-optical switch controlled with single photons and capable of operating at speeds exceeding 10 GHz [2].
In the second part of the talk, I will introduce an experimental system based on a laser-cooled atomic ensemble confined to a hollow-core photonic-crystal fiber [3]. So far, we demonstrated all-optical switching controlled with a few hundred photons [4], but the system has the potential to realize controllable cavity-free interactions between single photons. Finally, I will outline the future directions of this work that aim to combine the advantages of both the solid state and atom based strategies into a hybrid platform for scalable quantum technology systems.