Tuesday, July 17, 2012
Institute for Quantum Information Seminar
Strong photon-photon and photon-phonon interaction in quantum dot CQED
Arka Majumdar, Graduate Student, Electrical Engineering, Stanford University
Quantum dots (QDs) coupled to optical cavities constitute a scalable, robust, on-chip, semiconductor platform for probing fundamental cavity quantum electrodynamics, as well as for building classical and quantum information processing devices. Very strong interaction between light and matter can be achieved in this system as a result of the field localization inside sub-cubic wavelength volumes, leading to vacuum Rabi frequencies in the range of tens of GHz. We have employed a platform consisting of a single InAs QD in a GaAs photonic crystal cavity to study quantum optics and cavity QED. We probed the optical nonlinearity that occurs in the strong coupling regime, and employed it to perform classical optical switching at single photon level as well as to generate non-classical light. Additionally, we have been able to achieve an experimentally novel regime of cavity QED by strongly coupling a single QD to a photonic molecule consisting of two proximity-coupled cavities. Finally, we showed how the interaction of the quantum dot with acoustic phonons gives rise to novel phenomena unique to a solid state cavity QED system. We used such strong photon-phonon interaction to efficiently read out the QD states by the off-resonant cavity emission.