2011/09/29 by C. Roy, Stephen Hughes, Roy, Chiranjeeb +1 · 1 citation
Physics and Astronomy · Chemistry · Engineering · #Semiconductor Quantum Structures and Devices #Spectroscopy and Laser Applications #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.1109.6530
We present a quantum optics formalism to study intensity power broadening of\na semiconductor quantum dot interacting with an acoustic phonon bath and a high\nQ microcavity. Power broadening is investigated using a time-convolutionless\nmaster equation in the polaron frame which allows for a nonperturbative\ntreatment of the interaction of the quantum dot with the phonon reservoir. We\ncalculate the full non-Lorentzian photoluminescence (PL) lineshapes and\nnumerically extract the intensity linewidths of the quantum dot exciton and the\ncavity mode as a function of pump rate and temperature. For increasing field\nstrengths, multiphonon and multiphoton effects are found to be important, even\nfor phonon bath temperatures as low as 4 K. We show that the interaction of the\nquantum dot with the phonon reservoir introduces pronounced features in the\npower broadened PL lineshape, enabling one to observe clear signatures of\nelectron-phonon scattering. The PL lineshapes from cavity pumping and exciton\npumping are found to be distinctly different, primarily since the latter is\nexcited through the exciton-phonon reservoir. To help explain the underlying\nphysics of phonon scattering on the power broadened lineshape, an effective\nphonon Lindblad master equation derived from the full time-convolutionless\nmaster equation is introduced; we identify and calculate distinct Lindblad\nscattering contributions from electron-phonon interactions, including effects\nsuch as excitation-induced dephasing, incoherent exciton excitation and\nexciton-cavity feeding. Our effective phonon master equation is shown to\nreproduce the full intensity PL and the phonon-coupling effects very well,\nsuggesting that its general Lindblad form may find widespread use in\nsemiconductor cavity-QED.\n