排序方式: 共有20条查询结果,搜索用时 656 毫秒
1.
M. Le Vassor D’yerville D. Monge D. Cassagne J. P. Albert 《Optical and Quantum Electronics》2002,34(5-6):445-454
We present here a tight-binding-like modelling of two-dimensional (2D) photonic crystals (PCs). Adopted from solid-state physics,
the concept of generalized Wannier functions is used to construct a localized state basis that allows a parameter-free ab
initio study of defects in PCs. We demonstrate here for a 2D triangular lattice of dielectric rods in air, the existence of
this localized basis and the possibility to study large scale complex dielectric structures deviating from periodicity. Specific
numerical simulations on a split waveguide embedded in this triangular lattice are performed, and they demonstrate the superiority
of this method over plane wave based techniques. 相似文献
2.
3.
4.
5.
Emmanuel Centeno Eric Akmansoy Kevin Vynck David Cassagne Jean-Michel Lourtioz 《Photonics and Nanostructures》2010,8(2):120-124
Graded photonic crystals (GPhCs) have the remarkable ability to bend the path of light on the wavelength scale. A mirage effect has recently been reproduced experimentally in a two-dimensional structure made of metallic rods operating in the microwave regime (Akmansoy et al., 2008 [7]). This paper is intended to provide some theoretical insight onto the optical properties of metallic GPhCs and to report on the existence of a distinct regime of operation, in which light passes through the structure in a weakly curved trajectory. Experimental results are in good agreement with theoretical predictions, thereby further proving the ability of GPhCs to mold the flow of light in different ways at different frequencies. 相似文献
6.
V. Lisovskiy V. Yegorenkov J.-P. Booth S. Martins K. Landry D. Douai V. Cassagne 《Physics letters. A》2012
This Letter outlines the experimental study of molecule dissociation effect on rf capacitive discharge burning. We show that for each ammonia pressure value there exists some threshold rf voltage value below which the dissociation degree does not exceed 3%, but at higher rf voltage it grows to 30%. Increasing NH3 dissociation degree accelerates the discharge current growth against rf voltage. The rf discharge remains in a weak-current α-mode at low as well as at high dissociation degree because all ammonia dissociation products possess ionization potentials exceeding that for NH3. 相似文献
7.
A convenient route to phosphorus acylureas and acylsemicarbazides is reported. The syntheses of the new compounds involve the reaction between a chloroacetyl compound and various phosphorus starting materials (dithiophosphate, phosphine, phosphite and phosphinite). 相似文献
8.
9.
The construction of 3D photonic crystals with gaps in the visible or the near-infrared frequency range requires engineering of complex microstructures which are very difficult to realize by etching and micro-fabrication. Consequently, self-ordered systems such as synthetic opals are very promising. Synthetic bare opals are constituted by SiO2 spheres that organize themselves by a sedimentation process in a face centered cubic (fcc) arrangement. Using the plane wave method, we examine the photonic band structures of close-packed opal-based photonic crystals with an SiO2 (n = 1.5) matrix. The incomplete photonic band gaps at the X- and L-points have been studied which correspond to normally incident plane waves onto the (100) and (111) crystal planes. With the transfer matrix method, we model the transmission properties. We find that the incomplete gap at the L-point fully inhibits the transmission of waves propagating in the [111] direction for opal sample thicknesses that are easily obtainable. This property shows that bare opals could be good candidates for complete inhibition of transmission in the near-infrared and visible frequency range for given orientations. 相似文献
10.
A. Syntjoki M. Mulot K. Vynck D. Cassagne J. Ahopelto H. Lipsanen 《Photonics and Nanostructures》2008,6(1):42-VII
We show that photonic crystals with ring-shaped holes (RPhCs) exhibit superior properties compared to conventional photonic crystals (PhCs). At low air-fill factors RPhCs can have a larger bandgap than conventional PhCs. Moreover, RPhC waveguides with both high group index and small group velocity dispersion can be designed. RPhC waveguides are also more sensitive to external refractive index changes, which is attractive for sensor applications. Finally we set up a procedure to pattern RPhCs in silicon-on-insulator. 相似文献