37 research outputs found
Linewidth broadening of a quantum dot coupled to an off-resonant cavity
We study the coupling between a photonic crystal cavity and an off-resonant
quantum dot under resonant excitation of the cavity or the quantum dot.
Linewidths of the quantum dot and the cavity as a function of the excitation
laser power are measured. We show that the linewidth of the quantum dot,
measured by observing the cavity emission, is significantly broadened compared
to the theoretical estimate. This indicates additional incoherent coupling
between the quantum dot and the cavity.Comment: 5 pages, 4 figure
Quantum and classical information processing with a single quantum dot in photonic crystal cavity
The experiments show that the coupled QD-cavity system is a promising candidate for probing CQED as well as for optical information processing. Our present work includes building of a three level system in a QD coupled to cavity, which is essential for construction of any quantum information processing devices
Optical manipulation of quantum dot excitons strongly coupled to photonic crystal cavities
In this paper, we review some recent cavity quantum electrodynamic (CQED) experiments with single quantum
dot exciton coupled to photonic crystal cavities, performed in our group. We show how the coupled quantum-dot/cavity system can be used to modulate light with at a very fundamental level with very low power and
discuss some applications of these low power modulators
Independent electrical tuning of separated quantum dots in coupled photonic crystal cavities
Systems of photonic crystal cavities coupled to quantum dots are a promising
architecture for quantum networking and quantum simulators. The ability to
independently tune the frequencies of laterally separated quantum dots is a
crucial component of such a scheme. Here, we demonstrate independent tuning of
laterally separated quantum dots in photonic crystal cavities coupled by
in-plane waveguides by implanting lines of protons which serve to electrically
isolate different sections of a diode structure.Comment: 3 pages, 3 figure
Strain-tuning of quantum dot optical transitions via laser-induced surface defects
We discuss the fine-tuning of the optical properties of self-assembled
quantum dots by the strain perturbation introduced by laser-induced surface
defects. We show experimentally that the quantum dot transition red-shifts,
independently of the actual position of the defect, and that such frequency
shift is about a factor five larger than the corresponding shift of a
micropillar cavity mode resonance. We present a simple model that accounts for
these experimental findings.Comment: 9 pages, 6 figures. To appear in Phys. Rev.
Dynamic modulation of photonic crystal nanocavities using gigahertz acoustic phonons
Photonic crystal membranes (PCM) provide a versatile planar platform for
on-chip implementations of photonic quantum circuits. One prominent quantum
element is a coupled system consisting of a nanocavity and a single quantum dot
(QD) which forms a fundamental building block for elaborate quantum information
networks and a cavity quantum electrodynamic (cQED) system controlled by single
photons. So far no fast tuning mechanism is available to achieve control within
the system coherence time. Here we demonstrate dynamic tuning by monochromatic
coherent acoustic phonons formed by a surface acoustic wave (SAW) with
frequencies exceeding 1.7 gigahertz, one order of magnitude faster than
alternative approaches. We resolve a periodic modulation of the optical mode
exceeding eight times its linewidth, preserving both the spatial mode profile
and a high quality factor. Since PCMs confine photonic and phononic
excitations, coupling optical to acoustic frequencies, our technique opens ways
towards coherent acoustic control of optomechanical crystals.Comment: 11 pages 4 figure