Nonlinear Photonic Crystal Nanocavities and Waveguides

University Of Arizona, Tucson AZ

Investigators

Abstract

Objective. Evaluate the efficacy of phosphorous-based MBE-grown layers and quantum dots for quantum-limit strong coupling between a single quantum dot and a photonic crystal slab nanocavity (solid-state entanglement on a chip). Intellectual Merit. Following demonstration of strong coupling in 2004 in Tucson, worldwide progress toward improving the ratio of vacuum Rabi splitting to linewidth, as needed for practical applications in switching and quantum information, has been disappointingly slow. Since the limitation on linewidth is cavity Q, reported values as high as 700,000 for GaAs-slab/GaInP-sacrificial-layer empty cavities compared with typically 30,000 in GaAs/AlGaAs motivate this project to optimize the growth of P-based layers and dots for strong coupling. Success could transform the whole field of semiconductor cavity QED. Much of the P-based growth has been by MOCVD (apparently adequate for electronics and lasers), but the surfaces are too rough for fabrication of high-Q cavities. This project would first grow flat layers for empty high-Q cavities and then grow dots within the center of the slab. Broader Impacts. The principal impact of success would be much more robust semiconductor quantum devices, much less susceptible to dephasing caused by photon escape from low-Q cavities. This would make the devices much more useful for single photon switches and for quantum state transfer between internal states of separated cavities. Training of graduate students in quantum optics and the required experimental skills of cryogenics and spectroscopy is another important impact. Mentoring RET teachers and REU students helps attract bright students into scientific and engineering careers.