Applied Physics Seminar

Abstract

Interactions between light and matter lie at the heart of optical communication and information technology. Nanophotonic devices enhance light-matter interactions by confining photons to small mode volumes, enabling optical information processing at low energies.  In the strong coupling regime these interactions are sufficiently large to achieve a nonlinear response with a single photon.  Such single-photon nonlinearities are highly desirable for photonic quantum information where atoms mediate interactions between photonic qubits.  In this talk I will describe our effort to develop and coherently control quantum dots strongly coupled to photonic crystals.  Quantum dots are semiconductor "artificial atoms" that can act as efficient photon emitters and quantum memories.  By embedding them in a photonic crystal cavity that spatially confines photons to less than a cubic wavelength, we can attain the strong coupling regime. I will discuss how we can exploit this regime to achieve a quantum transistor, where a single spin can flip a photon polarization and a single photon can flip the spin-state, realizing a fundamental quantum interaction.  I will then describe how this device can implement a single photon transistor, where a single photon can switch an optical signal composed of as many as 30 photons.  Finally, I will discuss our recent effort to extend our results into the telecommunication wavelengths, and to improve the efficiency and scalability of the structure in order to attain integrated multi-dot devices on a single chip.

Biography

Edo Waks is a professor in the Department of Electrical and Computer Engineering at the University of Maryland, College Park.  He is also a member of the Joint Quantum Institute (JQI), a collaborative effort between the University of Maryland and NIST, Gaithersburg, dedicated to the study of quantum coherence.   Waks received his B.S. and M.S. from Johns Hopkins University, and his Ph.D. from Stanford University.  He is a recipient of a Presidential Early Career Award for Scientists and Engineers (PECASE), an NSF CAREER award, and ARO Young Investigator Award for the investigation of interactions between quantum dots and nanophotonic structures.  His current work focuses coherent control and manipulation semiconductor quantum dots, and their interactions with photonic crystal devices for creating strong atom-photon interactions.

***Refreshments at 2:30pm in Spalding 102.