Educação matemática pela arte
Gusmão, Lucimar Donizete
2013-08-28
Search results
47 records were found.
Self-phase modulation induced spectral broadening has been observed for ultrashort pulses propagating through Ta2O5 rib waveguide. The associated nonlinear refractive index was estimated to be 7.23 x10−19 m2/W, which is higher by one order of magnitude than silica glass.
We demonstrate experimentally the tuning of complete photonic band gaps in patterned silicon nitride waveguides. Transmission measurements were performed using an ultrabroadband high-brightness white light laser continuum, extracting extinction ratios as low as 10–4 in the gap regions. Angle-resolved measurements show the perfect alignment of the gap around the -J direction. © 2000 American Institute of Physics. [S0003-6951(00)02008-8]
Self-phase modulation induced spectral broadening has been observed for ultrashort pulses propagating through Ta2O5 rib waveguide. The associated nonlinear refractive index was estimated to be 7.23 x10−19 m2/W, which is higher by one order of magnitude than silica glass.
It is firmly established that periodic lattice structures can support photonic bandgaps (PBG). However, complete and absolute photonic bandgaps (CAPBG) have only been achieved in high dielectric constant mediums such as GaAs (=13.6). An artificial quasiperiodic photonic crystal based on the random square-triangle tiling system was designed and fabricated. The photonic quasicrystal possesses 12-fold symmetry and was analysed using a finite difference time domain (FDTD) approach. High orders of symmetry in photonic quasicrystals have been shown to provide isotropic bandgaps across all the directions of propagation of light. As an outcome of these properties, this new class of photonic quasicrystal has been shown, for the first time, to possess a secondary non-directional CAPBG for a relatively low index material, silicon nitride (=4.08)....
Photonic crystals are attracting current interest for a variety of reasons, such as their ability to inhibit the spontaneous emission of light. This and related properties arise from the formation of photonic bandgaps, whereby multiple scattering of photons by lattices of periodically varying refractive indices acts to prevent the propagation of electromagnetic waves having certain wavelengths. One route to forming photonic crystals is to etch two-dimensional periodic lattices of vertical air holes into dielectric slab waveguides. Such structures can show complete photonic bandgaps, but only for large-diameter air holes in materials of high refractive index (such as gallium arsenide, n = 3.69), which unfortunately leads to significantly reduced optical transmission when combined with optical fibres of low refractive index. It has been ...
We demonstrate experimentally the tuning of complete photonic band gaps in patterned silicon
nitride waveguides. Transmission measurements were performed using an ultrabroadband
high-brightness white light laser continuum, extracting extinction ratios as low as 1024 in the gap
regions. Angle-resolved measurements show the perfect alignment of the gap around the G-J
direction.
Self-phase modulation induced spectral broadening has been observed for ultrashort pulses propagating through Ta/W, which is higher by one order of magnitude than silica glass.
Here we report a simple and versatile technique for the preparation of novel macroporous three-dimensional gold and platinum films with regular submicron spherical holes arranged in a close-packed structure. Gold and platinum films were prepared by electrochemical reduction of gold or platinum complex ions dissolved in aqueous solution within the interstitial spaces between polystyrene latex spheres (500 or 750 nm in diameter) assembled on gold surfaces. The latex sphere templates were subsequently removed by dissolving in toluene to leave the structured metal films. Scanning electron microscopy of the gold and platinum films shows a well-formed regular three-dimensional, porous structure consisting of spherical voids arranged in a highly ordered face-centered cubic (fcc) structure. The spherical voids have the same diameter as the lat...
We demonstrate experimentally the tuning of complete photonic band gaps in patterned silicon nitride waveguides. Transmission measurements were performed using an ultrabroadband high-brightness white light laser continuum, extracting extinction ratios as low as 10–4 in the gap regions. Angle-resolved measurements show the perfect alignment of the gap around the -J direction. © 2000 American Institute of Physics. [S0003-6951(00)02008-8]
We describe the first non-destructive measurements of the evolution of the optical continuum along a non-linear waveguide. By utilizing near-field microscopy, the spectral variation can be imaged along and across the waveguide with sub-wavelength resolution.
