نتایج جستجو برای: waveguide theory

تعداد نتایج: 798126  

2016
Andrea Alù Mário G. Silveirinha Nader Engheta

Following our recent interest in metamaterial-based devices supporting resonant tunneling, energy squeezing, and supercoupling through narrow waveguide channels and bends, here we analyze the fundamental physical mechanisms behind this phenomenon using a transmission-line model. These theoretical findings extend our theory, allowing us to take fully into account frequency dispersion and losses ...

Journal: :Optics express 2011
André Kurs John D Joannopoulos Marin Soljačić Steven G Johnson

We present numerical experiments showing how coupled-mode theory can be systematically applied to join very dissimilar photonic crystal waveguides with 100% transmission. Our approach relies on appropriately tuning the coupling of the evanescent tail of a cavity mode to each waveguide. The transition region between the waveguides may be as short as a few lattice spacings. Moreover, this techniq...

Journal: :Physical review letters 2012
Daryl M Beggs Thomas F Krauss L Kuipers Tobias Kampfrath

We demonstrate, by theory and experiment, the ultrafast tilting of the dispersion curve of a photonic-crystal waveguide following the absorption of a femtosecond pump pulse. By shaping the pump-beam cross section with a nanometric shadow mask, different waveguide eigenmodes acquire different spatial overlap with the perturbing pump, leading to a local flattening of the dispersion by up to 11%. ...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2007
Zhuo Chen Ian R Hooper J Roy Sambles

A silver-dielectric-silver structure that supports both waveguide modes and surface plasmon polaritons is explored. The upper interface between the dielectric and the silver is periodically corrugated to allow coupling of visible photons to both types of mode. Such a metallic microcavity leads to plasmonic and waveguide self-interacting bandgaps at Brillouin zone boundaries. In addition there a...

Journal: :Optics express 2002
Philippe Lalanne A Talneau

We study adiabatic mode transformations in photonic-crystal integrated circuits composed of a triangular lattice of holes etched into a planar waveguide. The taper relies on the manufacture of holes with progressively-varying dimensions. The variation synthesizes an artificial material with a gradient effective index. Calculations performed with a three-dimensional exact electromagnetic theory ...

Journal: :Optics express 2011
Van Duong Ta Rui Chen Han Dong Sun

A modified hybrid waveguide with a wide-range coupling and long propagation has been proposed and the coupled mode theory has been applied to study the hybrid waveguide systematically. Two structures are comparatively discussed, namely, a dielectric wire and a circular capillary tube, which are buried in a polymer matrix and separated from the silver substrate by a gap. The simulated results in...

2007
Sanshui Xiao Niels Asger Mortensen

Optofluidic sensors based on highly dispersive two-dimensional photonic crystal waveguides are theoretically studied. Results show that these structures are strongly sensitive to the refractive index of the infiltrated liquid(nl), which is used to tune dispersion of the photonic crystal waveguide. Waveguide mode-gap edge shifts about 1.2 nm for δnl=0.002. The shifts can be explained well by ban...

Journal: :Physical review letters 2008
Brian Edwards Andrea Alù Michael E Young Mário Silveirinha Nader Engheta

Utilizing a microwave setup, we experimentally verify our recently developed theory of energy squeezing and tunneling [Phys. Rev. Lett. 97, 157403 (2006)10.1103/PhysRevLett.97.157403] through an ultranarrow waveguide channel that mimics zero-permittivity properties. Exploiting the infinite phase velocity supported by a waveguide transition section at cutoff, we test our theory of tunneling in t...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه مازندران - دانشکده علوم پایه 1386

چکیده ندارد.

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علم و صنعت ایران - دانشکده مهندسی برق 1386

هدف از ارائه پایان نامه شبیه سازی و طراحی نوع خاصی از فیلترهای موجبری صفحه e می باشد. تفاوت اصلی این فیلترها با نوع معمولی، وجود یک سری ساختارهای شیاردار به صورت متناوب در داخل رزوناتورهای آن ها می باشد. این رزوناتورها، به رزوناتورهای بار شده معروفند. به علت شکل ساختار و مشخص بودن شرایط مرزی آن، یکی از روش های مناسب، برای تحلیل این ساختار، روش تطبیق مودها می باشد. در فصل اول پایان نامه به بررسی...

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