979 research outputs found
Canonical quantization of macroscopic electrodynamics in a linear, inhomogeneous magneto-electric medium
We present a canonical quantization of macroscopic electrodynamics. The
results apply to inhomogeneous media with a broad class of linear
magneto-electric responses which are consistent with the Kramers-Kronig and
Onsager relations. Through its ability to accommodate strong dispersion and
loss, our theory provides a rigorous foundation for the study of quantum
optical processes in structures incorporating metamaterials, provided these may
be modeled as magneto-electric media. Previous canonical treatments of
dielectric and magneto-dielectric media have expressed the electromagnetic
field operators in either a Green function or mode expansion representation.
Here we present our results in the mode expansion picture with a view to
applications in guided wave and cavity quantum optics.Comment: Submitted to Physical Review A 24/07/201
Coupled-mode theory for periodic side-coupled microcavity and photonic crystal structures
We use a phenomenological Hamiltonian approach to derive a set of coupled
mode equations that describe light propagation in waveguides that are
periodically side-coupled to microcavities. The structure exhibits both Bragg
gap and (polariton like) resonator gap in the dispersion relation. The origin
and physical significance of the two types of gaps are discussed. The
coupled-mode equations derived from the effective field formalism are valid
deep within the Bragg gaps and resonator gaps.Comment: 13 pages, 6 figure
Optical injection and terahertz detection of the macroscopic Berry curvature
We propose an experimental scheme to probe the Berry curvature of solids. Our
method is sensitive to arbitrary regions of the Brillouin zone, and employs
only basic optical and terahertz techniques to yield a background free signal.
Using semiconductor quantum wells as a prototypical system, we discuss how to
inject Berry curvature macroscopically, and probe it in a way that provides
information about the underlying microscopic Berry curvature.Comment: 4 pages, accepted in Physical Review Letter
Truly unentangled photon pairs without spectral filtering
We demonstrate that an integrated silicon microring resonator is capable of
efficiently producing photon pairs that are completely unentangled; such pairs
are a key component of heralded single photon sources. A dual-channel
interferometric coupling scheme can be used to independently tune the quality
factors associated with the pump and signal and idler modes, yielding a
biphoton wavefunction with Schmidt number arbitrarily close to unity. This will
permit the generation of heralded single photon states with unit purity.Comment: 5 pages, 3 figure
Tailoring second-harmonic generation in birefringent poled fiber via Twist
We predict theoretically and demonstrate experimentally the ability to generate and control the strengths of various second-harmonic signals in birefringent poled fiber. This is done by simply twisting the fiber
Coherent spin dynamics in quantum wells in quantizing magnetic field
We investigate theoretically the coherent longitudinal and transversal spin
relaxation of photoexcited electrons in quantum wells in quantized magnetic
fields. We find the relaxation time for typical quantum well parameters between
100 and 1000 ps. For a realistic random potential the relaxation process
depends on the electron energy and g-factor, demonstrating oscillations in the
spin polarization accompanying the spin relaxation. The dependence of spin
relaxation on applied field, and thus on the corresponding "magnetic" length,
can be used to characterize the spatial scale of disorder in quantum wells.Comment: 13 pages, 4 figure
Second and Third Harmonic Generation in Metal-Based Nanostructures
We present a new theoretical approach to the study of second and third
harmonic generation from metallic nanostructures and nanocavities filled with a
nonlinear material, in the ultrashort pulse regime. We model the metal as a
two-component medium, using the hydrodynamic model to describe free electrons,
and Lorentz oscillators to account for core electron contributions to both the
linear dielectric constant and to harmonic generation. The active nonlinear
medium that may fill a metallic nanocavity, or be positioned between metallic
layers in a stack, is also modeled using Lorentz oscillators and surface
phenomena due to symmetry breaking are taken into account. We study the effects
of incident TE- and TM-polarized fields and show that a simple re-examination
of the basic equations reveals additional exploitable dynamical features of
nonlinear frequency conversion in plasmonic nanostructures.Comment: 33 pages, including 11 figures and 74 references; corrected
affiliations and some typo
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