The Experts below are selected from a list of 156630 Experts worldwide ranked by ideXlab platform

Yidong Huang - One of the best experts on this subject based on the ideXlab platform.

Sharee J Mcnab - One of the best experts on this subject based on the ideXlab platform.

  • active control of slow light on a chip with photonic crystal waveguides
    Nature, 2005
    Co-Authors: Yurii A Vlasov, Martin P Oboyle, Hendrik F Hamann, Sharee J Mcnab
    Abstract:

    Photonic crystals could become the silicon chips of optoelectronics, engineered to control the properties of photons in much the same way that the atomic lattice of a semiconductor controls electrons. Yurii Vlasov and co-workers at IBM's T. J. Watson Research Center have applied photonic crystal technology to ‘slow light’. In this still-new field, pulses of light are drastically slowed and even brought to a halt in various atomic and solid-state systems where Material Absorption is countered by optical pumping. This has potential in applications ranging from all-optical storage to optical switching. Vlasev et al. demonstrate an over 300-fold reduction of the group velocity of a light pulse on a silicon chip via an ultra-compact photonic integrated circuit utilizing low-loss silicon photonic crystal waveguides. The cover shows a scanning electron micrograph of the experimental setup. It is known that light can be slowed down in dispersive Materials near resonances1. Dramatic reduction of the light group velocity—and even bringing light pulses to a complete halt—has been demonstrated recently in various atomic2,3,4,5 and solid state systems6,7,8, where the Material Absorption is cancelled via quantum optical coherent effects3,4,5,7. Exploitation of slow light phenomena has potential for applications ranging from all-optical storage to all-optical switching9,10. Existing schemes, however, are restricted to the narrow frequency range of the Material resonance, which limits the operation frequency, maximum data rate and storage capacity10. Moreover, the implementation of external lasers, low pressures and/or low temperatures prevents miniaturization and hinders practical applications. Here we experimentally demonstrate an over 300-fold reduction of the group velocity on a silicon chip via an ultra-compact photonic integrated circuit using low-loss silicon photonic crystal waveguides11,12 that can support an optical mode with a submicrometre cross-section13,14. In addition, we show fast (∼100 ns) and efficient (2 mW electric power) active control of the group velocity by localized heating of the photonic crystal waveguide with an integrated micro-heater.

Xiangdong Li - One of the best experts on this subject based on the ideXlab platform.

Maksim Skorobogatiy - One of the best experts on this subject based on the ideXlab platform.

  • Planar Porous THz Waveguides for Low-Loss Guidance and Sensing Applications
    IEEE Transactions on Terahertz Science and Technology, 2013
    Co-Authors: Andrey Markov, A. Mazhorova, Maksim Skorobogatiy
    Abstract:

    Planar porous dielectric waveguides featuring periodic sequence of deeply subwavelength air/dielectric bi-layers are proposed, fabricated and characterized in view of their potential applications as low-loss waveguides and sensors in the THz spectral range. The waveguide design maximizes the fraction of power guided in the air to reduce waveguide loss due to Material Absorption, as well as to provide a conveniently accessible microfluidic channels for sensor measurements.

  • Designs of porous polymer THz fibers
    Ultrafast Phenomena in Semiconductors and Nanostructure Materials XII, 2008
    Co-Authors: Alexandre Dupuis, Alireza Hassani, Maksim Skorobogatiy
    Abstract:

    We propose various designs of porous polymer fibers for guiding terahertz radiation. Numerical simulations are presented for three fiber geometries: a Bragg fiber consisting of periodic multilayers of ferroelectric polyvinylidene fluoride (PVDF) and polycarbonate (PC), a sub-wavelength waveguide containing multiple sub-wavelength holes, as well as a cobweb-like porous Bragg fiber consisting of solid film layers suspended by a network of bridges. Various properties of these fibers are presented. Emphasis is put on the optimization of the geometries to increase the fraction of power guided in the air, thereby alleviating the effects of Material Absorption. Losses of about 10 dB/m, 7.8 dB/m, and 1.7 dB/m at 1 THz are respectively predicted for these three structures.

  • low loss asymptotically single mode propagation in large core omniguide fibers
    Optics Express, 2001
    Co-Authors: Steven G Johnson, Maksim Skorobogatiy, Marin Soljacic, Mihai Ibanescu, Ori Weisberg, Torkel Engeness, Steven A Jacobs, J D Joannopoulos, Yoel Fink
    Abstract:

    We present the light-propagation characteristics of OmniGuide fibers, which guide light by concentric multi-layer dielectric mirrors having the property of omnidirectional reflection. We show how the lowest-loss TE01 mode can propagate in a single-mode fashion through even large-core fibers, with other modes eliminated asymptotically by their higher losses and poor coupling, analogous to hollow metallic microwave waveguides. Dispersion, radiation leakage, Material Absorption, nonlinearities, bending, acircularity, and interface roughness are considered with the help of leaky modes and perturbation theory, and both numerical results and general scaling relations are presented. We show that cladding properties such as Absorption and nonlinearity are suppressed by many orders of magnitude due to the strong confinement in a hollow core, and other imperfections are tolerable, promising that the properties of silica fibers may be surpassed even when nominally poor Materials are employed.

S.i. Najafi - One of the best experts on this subject based on the ideXlab platform.

  • Length optimization of single-mode rare-earth doped waveguides using saturated Absorption
    IEEE Photonics Technology Letters, 1995
    Co-Authors: V. Francois, T. Ohtsuki, N. Peyghambarian, S.i. Najafi
    Abstract:

    Absorption saturation was demonstrated to provide a high, uniform population inversion over a length of waveguide longer than the Material Absorption length. The small signal gain was measured experimentally in single-mode waveguides, made by silver ion exchange, on a commercially available neodymium doped glass. The ratio of the excited states was calculated as a function of waveguide length and was shown to be a convenient criteria to determine the optimum device length.