Search results for "Photonic crystals"

Parametric Solitons in Two-Dimensional Lattices of Purely Nonlinear Origin

2008

We demonstrate spatial solitons via twin-beam second-harmonic generation in hexagonal lattices realized by poling lithium niobate planar waveguides. These simultons can be steered by acting on power, direction, and wavelength of the fundamental frequency input.

Resonant Interaction Energy between Two Identical Atoms in a Photonic Crystal

2014

We consider the resonant interaction energy between two identical atoms, one in an excited state and the other in the ground state, placed inside a photonic crystal. We consider two different models of a photonic crystal: a one-dimensional crystal and an isotropic three-dimensional crystal. The two atoms, having the same orientation of their transition dipole moment, are supposed prepared in their entangled symmetrical state and interacting with the quantum electromagnetic field in the multipolar coupling scheme. We consider both the case of an atomic transition frequency outside the photonic band gap and the case of a transition frequency inside the gap. When the transition frequency is ou…

Spatial Solitons in Quadratic 2D Nonlinear Photonic Crystals

2007

We report on the first investigations into parametric solitary-wave formation in 2D nonlinear photonic crystals and present experimental results obtained in an hexagonally poled LiNbO3 waveguide designed for twin-beam second harmonic generation at telecom wavelengths.

Exploring integration prospects of opal-based photonic crystals

2003

Different methods of functionalisation of thin opal films are discussed, including synthesis of opals on pre-patterned substrates, post-synthesis electron beam lithography, preparation of opals with heterogeneous photonic band gap structure and integrating opals with light sources. These approaches have been tested experimentally and key technological problems have been identified.

Light self-confinement via second harmonic generation in a 2D nonlinear photonic crystal waveguide

2007

Spatial solitary waves induced by quadratic nonlinearities have been the subject of many theoretical and experimental investigations in the last decade, with extensive studies being devoted to soliton formation in 1D nonlinear photonic crystals (NPC) such as PPLN (periodically poled LiNbO3). Here we present results on a new class of (1 + 1)D spatial solitary waves, the first examples of quadratic self-confinement in a 2D NPC.

Micromoulding of three-dimensional photonic crystals on silicon substrates

2003

International audience; The growth of three-dimensional photonic crystals (PhCs) on patterned silicon substrates is reported. It is shown that deep trenches can be uniformly filled by a self-assembly of polymer microspheres, in a close-packed face-centred cubic lattice. The crystalline quality is compared for different channel widths. These observations are confirmed by optical reflectance measurements in the visible range, showing a bandwidth of enhanced reflection. The possibility to detach the PhC, i.e. to use the substrate as a mould, is also demonstrated. The potential of this approach for building PhC-based complex architectures is discussed.

All-optical tuning of a photonic band-gap via near-infrared laser pulses

2008

We present an all-optical tuning at IR wavelength in a novel photonic crystal consisting of a polystyrene opal with gold nanoparticles. The band-gap can be finely tuned with permanent shifts as large as 30 nm irradiating the sample with ps pulses at a low rep-rate in the visible.

Ethanol vapor optical sensors based on polystyrene opals infiltrated with hydrogel

2013

Hyperspectral near-field imaging : development and applications to nanophotonics devices

2013

The scanning near-field optical microscopy (SNOM) is used to analyze optical phenomena at the sub-wavelength scale such as light localization and propagation in photonic crystals or plasmonic devices. In any case, SNOM experiments rely on the positioning of a local probe in the optical near field of a given structure and on the detection of the surrounding evanescent waves. Depending on the nature of the probe or on the optical detection method, the detected physical properties are the spatial distributions of the amplitude and phase or the intensity of the electric and magnetic components of the probed field. We present here the implementation of an innovative hyperspectral near-field imag…

2D photonic defect layers in 3D inverted opals on Si platforms

2006

Dielectric spheres synthesised for the fabrication of self-organized photonic crystals such as opals offer large opportunities for the design of novel nanophotonic devices. In this paper, we show a hexagonal superlattice monolayer of dielectric spheres inscribed on a 3D colloidal photonic crystal by e-beam lithography. The crystal is produced by a variation of the vertical drawing deposition method assisted by an acoustic field. The structures were chosen after simulations showed that a hexagonal super-lattice monolayer in air exhibits an even photonic band gap below the light cone if the refractive index of the spheres is higher than 1.93.