Cavity QED with a Single Quantum Dot in a Photonic Crystal Cavity: Photon Blockade, Dressed States, and Controlled Phase Shift

Stanford University, Stanford CA

Investigators

Abstract

***NON-TECHNICAL ABSTRACT*** A quantum dot is a nanoscale chunk of one semiconductor material inside of another, which acts as a box for the electrons within it, while an optical nanocavity resonantly recirculates light inside of its nanoscale volume. It has recently been shown that a system consisting of a single quantum dot embedded inside of an optical nanocavity can be employed as a practical platform to study various new regimes of interaction between light and matter, even at a level of only one particle of light called photon. This single investigator proposal focuses on performing a series of experiments on this platform, including the observation of true quantum mechanical states of coupled light and matter (called the dressed states), photon blockade (the regime in which the presence of one photon inside of a nanocavity prohibits another photon from entering it), and the controlled interaction between only two photons mediated by such a system (controlled phase shift). In addition to probing new regimes of quantum and nanoscale physics, this system can be used to develop a more practical platform for quantum communication and quantum computing - systems based on powerful properties of quantum mechanics which have the potential to revolutionize information technology, security, and even drug discovery. Over the course of this project, a number of students will be trained in state of the art optical techniques, and will gain expertise in an area that bridges many disciplines of physics and engineering, which will prepare them for work in academia, industry or government. The project receives support from the Divisions of Materials Research and Physics. ***TECHNICAL ABSTRACT*** Solid-state cavity quantum electrodynamics (QED) systems based on photonic crystal nanocavities and semiconductor quantum dots have seen rapid progress. Recent photoluminescence experiments have led to the observation of weak and strong coupling regimes of light-matter interaction. In addition, resonant light scattering has provided a means to directly probe cavity-quantum dot coupling. This single investigator project focuses on probing the quantum states of light, as well as cavity QED, in such a solid state system. In order to obtain an improved understanding of light-matter interactions, the project will attempt to observe dressed states of the cavity QED system, photon blockade, and controlled phase shifts at a single photon level (i.e., a nonlinear interaction between two individual photons mediated by such a system). In addition, the system can be used to develop a more practical platform for quantum communication and quantum computing, as well as for ultra low power all-optical computing. Over the course of this project, a number of students will be trained in state of the art optical techniques, and will gain expertise in an area that bridges many disciplines of physics and engineering, ranging from quantum optics, quantum information science, and mesoscopic physics, to photonics and optoelectronics. The project receives support from the Divisions of Materials Research and Physics.