1,405 research outputs found
Sharp bends in photonic crystal waveguides as nonlinear Fano resonators
We demonstrate that high transmission through sharp bends in photonic crystal
waveguides can be described by a simple model of the Fano resonance where the
waveguide bend plays a role of a specific localized defect. We derive effective
discrete equations for two types of the waveguide bends in two-dimensional
photonic crystals and obtain exact analytical solutions for the resonant
transmission and reflection. This approach allows us to get a deeper insight
into the physics of resonant transmission, and it is also useful for the study
and design of power-dependent transmission through the waveguide bends with
embedded nonlinear defects.Comment: 8 pages, 5 figures, submitted to Optics Expres
Low-threshold bistability of slow light in photonic-crystal waveguides
We analyze the resonant transmission of light through a photonic-crystal
waveguide side coupled to a Kerr nonlinear cavity, and demonstrate how to
design the structure geometry for achieving bistability and all-optical
switching at ultra-low powers in the slow-light regime. We show that the
resonance quality factor in such structures scales inversely proportional to
the group velocity of light at the resonant frequency and thus grows
indefinitely in the slow-light regime. Accordingly, the power threshold
required for all-optical switching in such structures scales as a square of the
group velocity, rapidly vanishing in the slow-light regime.Comment: LaTeX, 6 pages, 4 figure
Low-threshold bistability of slow light in photonic-crystal waveguides
We analyze the resonant transmission of light through a
photonic-crystal waveguide side coupled to a Kerr nonlinear cavity, and
demonstrate how to design the structure geometry for achieving bistability
and all-optical switching at ultralow powers in the slow-light regime. We
show that the resonance quality factor in such structures scales inversely
proportional to the group velocity of light at the resonant frequency
and thus grows indefinitely in the slow-light regime. Accordingly, the
power threshold required for all-optical switching in such structures scales
as a square of the group velocity, rapidly vanishing in the slow-light regime
Self-trapping of light and nonlinear localized modes in 2D photonic crystals and waveguides
We overview our recent results on the nonlinear localized modes in
two-dimensional (2D) photonic crystals and photonic-crystal waveguides.
Employing the technique based on the Green function, we describe the existence
domains for nonlinear guided modes in photonic crystal waveguides and study
their unique properties including bistability. We also show that low-amplitude
nonlinear modes near the band edge of a reduced-symmetry 2D square-lattice
photonic crystals, which are usually unstable, can be stabilized due to
effective long-range linear and nonlinear interactions.Comment: 20 pages (LaTeX) with 12 figures (EPS
Towards all-dielectric metamaterials and nanophotonics
We review a new, rapidly developing field of all-dielectric nanophotonics
which allows to control both magnetic and electric response of structured
matter by engineering the Mie resonances in high-index dielectric
nanoparticles. We discuss optical properties of such dielectric nanoparticles,
methods of their fabrication, and also recent advances in all-dielectric
metadevices including couple-resonator dielectric waveguides, nanoantennas, and
metasurfaces
Coupled-resonator optical waveguide: a proposal and analysis
We propose a new type of optical waveguide that consists of a sequence of coupled high- Q resonators. Unlike other types of optical waveguide, waveguiding in the coupled-resonator optical waveguide (CROW) is achieved through weak coupling between otherwise localized high- Q optical cavities. Employing a formalism similar to the tight-binding method in solid-state physics, we obtain the relations for the dispersion and the group velocity of the photonic band of the CROW's and find that they are solely characterized by coupling factor k 1 . We also demonstrate the possibility of highly efficient nonlinear optical frequency conversion and perfect transmission through bends in CROW's
Coupled-resonator-induced reflection in photonic-crystal waveguide structures
We study the resonant transmission of light in a coupled-resonator optical
waveguide interacting with two nearly identical side cavities. We reveal and
describe a novel effect of the coupled-resonator-induced reflection (CRIR)
characterized by a very high and easily tunable quality factor of the
reflection line, for the case of the inter-site coupling between the cavities
and the waveguide. This effect differs sharply from the
coupled-resonator-induced transparency (CRIT) -- an all-optical analogue of the
electromagnetically-induced transparency -- which has recently been studied
theoretically and observed experimentally for the structures based on
micro-ring resonators and photonic crystal cavities. Both CRIR and CRIT effects
have the same physical origin which can be attributed to the Fano-Feshbach
resonances in the systems exhibiting more than one resonance. We discuss the
applicability of the novel CRIR effect to the control of the slow-light
propagation and low-threshold all-optical switching.Comment: LaTeX, 11 pages, 5 figure
Efficient analysis and design of low-loss whispering-gallery-mode coupled resonator optical waveguide bends
Waveguides composed of electromagnetically-coupled optical microcavities
(coupled resonator optical waveguides or CROWs) can be used for light guiding,
slowing and storage. In this paper, we present a two-dimensional analysis of
finite-size straight and curved CROW sections based on a rigorous Muller
boundary integral equations method. We study mechanisms of the coupling of
whispering gallery (WG) modes and guiding light around bends in CROWs composed
of both identical and size-mismatched microdisk resonators. Our accurate
analysis reveals differences in WG modes coupling in the vicinity of bends in
CROWs composed of optically-large and wavelength-scale microcavities. We
propose and discuss possible ways to design low-loss CROW bends and to reduce
bend losses. These include selecting specific bend angles depending on the
azimuthal order of the WG mode and tuning the radius of the microdisk
positioned at the CROW bend.Comment: 8 pages with 10 figures (to appear in IEEE/OSA J. Lightwave
Technology, 2007
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