Efficient transmission of crossing dielectric slot waveguides.

Physics Department, Northeast Forestry University, Harbin, China.
Optics Express (Impact Factor: 3.55). 02/2011; 19(5):4756-61. DOI: 10.1364/OE.19.004756
Source: PubMed

ABSTRACT Transmission properties of two crossing dielectric slot waveguides (Si-Air-Si) are investigated using the finite difference in time domain method. Results show that the low transmission of this system mainly results from the reflection and radiation loss rather than the crosstalk. Using a simple method of filling up the crossing slots locally, the reflection, radiation losses and crosstalk are all greatly suppressed. With moderate parameters in this paper, the transmission efficient increases from 35.0% to more than 97% in a wide range of wavelength around 1.55 mm. The results and method presented in this paper may be very useful in the application of slot waveguide in micro and nano photonics.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a numerical analysis of surface plasmon waveguides exhibiting both long-range propagation and spatial confinement of light with lateral dimensions of less than 10% of the free-space wavelength. Attention is given to characterizing the dispersion relations, wavelength-dependent propagation, and energy density decay in two-dimensional Ag/SiO2/Ag structures with waveguide thicknesses ranging from 12 nm to 250 nm. As in conventional planar insulator-metal-insulator (IMI) surface plasmon waveguides, analytic dispersion results indicate a splitting of plasmon modes—corresponding to symmetric and antisymmetric electric field distributions—as SiO2 core thickness is decreased below 100 nm. However, unlike IMI structures, surface plasmon momentum of the symmetric mode does not always exceed photon momentum, with thicker films (d~50 nm) achieving effective indices as low as n=0.15. In addition, antisymmetric mode dispersion exhibits a cutoff for films thinner than d=20 nm, terminating at least 0.25 eV below resonance. From visible to near infrared wavelengths, plasmon propagation exceeds tens of microns with fields confined to within 20 nm of the structure. As the SiO2 core thickness is increased, propagation distances also increase with localization remaining constant. Conventional waveguiding modes of the structure are not observed until the core thickness approaches 100 nm. At such thicknesses, both transverse magnetic and transverse electric modes can be observed. Interestingly, for nonpropagating modes (i.e., modes where propagation does not exceed the micron scale), considerable field enhancement in the waveguide core is observed, rivaling the intensities reported in resonantly excited metallic nanoparticle waveguides.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigate the properties of the modes that are supported by 3-D subwavelength plasmonic slot waveguides. We first show that the fundamental mode that is supported by a symmetric plasmonic slot waveguide, which is composed of a subwavelength slot in a thin metallic film embedded in an infinite homogeneous dielectric, is always a bound mode for any combination of operating wavelength and waveguide parameters. Its modal fields are highly confined over a wavelength range extending from zero frequency to the ultraviolet. We then show that for an asymmetric plasmonic slot waveguide, in which the surrounding dielectric media above and below the metal film are different, there may exist a cutoff slot width and/or a cutoff metal film thickness above which the mode becomes leaky, and there always exists a cutoff wavelength above which the mode becomes leaky. We investigate in detail the effect of variations of the parameters of the symmetric and asymmetric plasmonic slot waveguides. We also consider related alternative 3-D plasmonic waveguide geometries, such as a plasmonic slot waveguide, in which the two metal film regions that form the slot have a finite width, and a plasmonic strip waveguide, which is formed between a metallic strip and a metallic substrate. We show that for a specific modal size, the fundamental mode of the standard plasmonic slot waveguide has a larger propagation length compared with the corresponding modes of these plasmonic waveguides.
    Journal of Lightwave Technology 10/2007; 25(9):2511-2521. · 2.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a novel waveguide geometry for enhancing and confining light in a nanometer-wide low-index material. Light enhancement and confinement is caused by large discontinuity of the electric field at high-index-contrast interfaces. We show that by use of such a structure the field can be confined in a 50-nm-wide low-index region with a normalized intensity of 20 microm(-2). This intensity is approximately 20 times higher than what can be achieved in SiO2 with conventional rectangular waveguides.
    Optics Letters 07/2004; 29(11):1209-11. · 3.39 Impact Factor


Available from
May 26, 2014