557 research outputs found
Spatially Adiabatic Frequency Conversion in Optoelectromechanical Arrays
Faithful conversion of quantum signals between microwave and optical
frequency domains is crucial for building quantum networks based on
superconducting circuits. Optoelectromechanical systems, in which microwave and
optical cavity modes are coupled to a common mechanical oscillator, are a
promising route towards this goal. In these systems, efficient, low-noise
conversion is possible using a mechanically dark mode of the fields but the
conversion bandwidth is limited to a fraction of the cavity linewidth. Here, we
show that an array of optoelectromechanical transducers can overcome this
limitation and reach a bandwidth that is larger than the cavity linewidth. The
coupling rates are varied in space throughout the array so that the
mechanically dark mode of the propagating fields adiabatically changes from
microwave to optical or vice versa. This strategy also leads to significantly
reduced thermal noise with the collective optomechanical cooperativity being
the relevant figure of merit. Finally, we demonstrate that, quite surprisingly,
the bandwidth enhancement per transducer element is largest for small arrays;
this feature makes our scheme particularly attractive for state-of-the-art
experimental setups.Comment: 18 pages, 10 figures (including Supplemental Material
Interfacing single photons and single quantum dots with photonic nanostructures
Photonic nanostructures provide means of tailoring the interaction between
light and matter and the past decade has witnessed a tremendous experimental
and theoretical progress in this subject. In particular, the combination with
semiconductor quantum dots has proven successful. This manuscript reviews
quantum optics with excitons in single quantum dots embedded in photonic
nanostructures. The ability to engineer the light-matter interaction strength
in integrated photonic nanostructures enables a range of fundamental
quantum-electrodynamics experiments on, e.g., spontaneous-emission control,
modified Lamb shifts, and enhanced dipole-dipole interaction. Furthermore,
highly efficient single-photon sources and giant photon nonlinearities may be
implemented with immediate applications for photonic quantum-information
processing. The review summarizes the general theoretical framework of photon
emission including the role of dephasing processes, and applies it to photonic
nanostructures of current interest, such as photonic-crystal cavities and
waveguides, dielectric nanowires, and plasmonic waveguides. The introduced
concepts are generally applicable in quantum nanophotonics and apply to a large
extent also to other quantum emitters, such as molecules, nitrogen vacancy
ceters, or atoms. Finally, the progress and future prospects of applications in
quantum-information processing are considered.Comment: Updated version resubmitted to Reviews of Modern Physic
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