Lecture by Prof. S. Hughes, Queen’s University, Kingston, Ontario, Canada

Phonon-modified photon emission dynamics from quantum dots in a structured photonic reservoir


Abstract
The spontaneous emission rate of a two-level atom coupled to a structured photonic reservoir is determined by the (projected) local density of photonic states (LDOS) at the emitter frequency, according to Fermi’s golden rule. Such a relation is also supposed to hold true for semiconductor quantum dots (QDs), which behave as artificial atoms in a solid state medium. A sharp atom-like resonance along with an ability to couple to microcavity structures such as photonic crystal reservoirs makes QDs promising as scalable qubits at optical frequencies. However, coupling with phonons renders a QD different compared to a simple two-level atom, as has been demonstrated in a number of recent experiments. In this talk, I will describe how the spontaneous emission rate of a QD coupled to structured photonic reservoir is actually determined by the broadband frequency dependence of the LDOS, in clear violation of Fermi’s golden rule. A significant breakdown of Fermi’s golden rule occurs when the damping rates of the phonon bath and photon bath compare. I will present examples for QDs in simple Lorentzian cavities, coupled resonator optical waveguides (CROWs), and realistic slow-light photonic crystal waveguides. I will also make a connection to emerging experiments and show how phonons influence the nonlinear emission dynamics in the regime of coherent excitation, manifesting in a dynamical interplay between photon and phonon dynamics.

Time

Tue 15 Dec 15
11:00 - 12:00

Organizer

DTU Fotonik

Where

Lyngby Campus

Building 343, room 005