Search results for "Photonic Crystal"
showing 10 items of 218 documents
Hyperspectral optical near-field imaging: Looking graded photonic crystals and photonic metamaterials in color
2012
International audience; Using a scanning near-field optical microscope operating with a hyperspectral detection scheme, we report the direct observation of the mirage effect within an on-chip integrated artificial material made of a two dimensional graded photonic crystal. The light rainbow due to the material dispersion is quantified experimentally and quantitatively compared to three dimensional plane wave assisted Hamiltonian optics predictions of light propagation.
Fabrication of polarizing photonic crystal fibres and photonic crystal fibre tapers: Applications
2007
We report the fabrication of an anisotropic photonic crystal fibre with polarization properties and photonic crystal fibre tapers for supercontinuum generation. The anisotropy of the fibre was created by enlarging four airholes next to the silica core. Different polarization regimes as a function of the geometric parameters, including polarizing behaviour at 1.55 mum, were obtained. In the second part of the paper, we report the fabrication of photonic crystal fibre tapers. We present experimental results on supercontinuum generation in photonic crystal fibre tapers using quasi-continuous pump pulses of 7 ns duration at 532 nm and at 1064 nm.
3D Colloidal photonic crystal fabrication improved by AC fields for frequency conversion enhancement in photovoltaics
2011
We report on the fabrication of high-quality 3D colloidal photonic crystals, whose finality is to modify the emission properties of frequency converters for photovoltaic applications. The band structure of the photonic crystals can be used to enhance the emission of down- and up-converters materials embedded in the 3D structures. However, in order to achieve an efficient conversion the first step is to obtain highly ordered templates with appropriated dimensions. We analyze here the photonic crystals obtained by the dip-coating or vertical deposition method. Moreover, by using perpendicular AC fields during the assembly of the nanospheres, the quality of the packed structures has been impro…
Numerical study on localized defect modes in two-dimensional lattices: a high Q-resonant cavity
2003
Abstract The spectral widths and the quality factors of defect modes localized for different defects structures formed in a 2D photonic crystal composed of a square lattice of circular rods of indium antimonide (InSb) are theoretically investigated. It is first shown that some factors such as the lattice nature, the line defect orientation, the nature and the defect width have a significant influence on the optical properties of the studied structures and can improve the Q factor and defect peak transmission intensity. Particularly, the transmission spectra of the defects calculated by means the transfer-matrix-method for a particular structure of eight line defects introduced in its center…
Polarization Modulation Instability in Dispersion-Engineered Photonic Crystal Fibers
2021
Generation of widely spaced polarization modulation instability (PMI) sidebands in a wide collection of photonic crystal fibers (PCF), including liquid-filled PCFs, is reported. The contribution of chromatic dispersion and birefringence to the net linear phase mismatch of PMI is investigated in all-normal dispersion PCFs and in PCFs with one (or two) zero dispersion wavelengths. Large frequency shift sidebands are demonstrated experimentally. Suitable fabrication parameters for air-filled and liquid-filled PCFs are proposed as guidelines for the development of dual-wavelength light sources based on PMI.
Inverted-opal photonic crystals for ultra light-trapping in solar cells
2010
We investigated a three dimensional inverted opal having the potential to notably increase light-trapping in solar cells. The 3D photonic crystal top layer is an angle- and direction-selective filter, which decreases the acceptance cone of the solar cell. Numerical optimisation methods are used to verify the optical and electrical properties for a large angluar and energy spectrum for a system consisting of an inverted opal on top of a thin crystalline silicon solar cell. It is numerically shown that an inverted opal grown in the Τ - Xdirection might fulfill the requirement for such a filter. An estimate for the theoretically achievable efficiency for nonconcentrated light is presented that…
An E-plane EBG waveguide for dispersion compensated transmission of short pulses
2007
The resolution of radar applications can significantly suffer from pulse broadening along the propagation in homogeneous hollow waveguides. The latter occurs due to the strongly dispersive nature of the fast waves in the waveguides. A low-cost solution to this problem is here proposed, employing an EBG type of waveguide, compatible with traditional E-plane fabrication techniques. By means of an example, here we demonstrate the reduction of the pulse spreading as it propagates along this type of waveguide.
Graded-index optical fiber emulator of an interacting three-atom system: illumination control of particle statistics and classical non-separability
2019
[EN] We show that a system of three trapped ultracold and strongly interacting atoms in one-dimension can be emulated using an optical fiber with a graded-index profile and thin metallic slabs. While the wave-nature of single quantum particles leads to direct and well known analogies with classical optics, for interacting many-particle systems with unrestricted statistics such analoga are not straightforward. Here we study the symmetries present in the fiber eigenstates by using discrete group theory and show that, by spatially modulating the incident field, one can select the atomic statistics, i.e., emulate a system of three bosons, fermions or two bosons or fermions plus an additional di…
Coherent Control of Stimulated Emission inside one dimensional Photonic Crystals:Strong Coupling regime
2006
The present paper discusses the stimulated emission, in strong coupling regime, of an atom embedded inside a one dimensional (1D) Photonic Band Gap (PBG) cavity which is pumped by two counter-propagating laser beams. Quantum electrodynamics is applied to model the atom-field interaction, by considering the atom as a two level system, the e.m. field as a superposition of normal modes, the coupling in dipole approximation, and the equations of motion in Wigner-Weisskopf and rotating wave approximations. In addition, the Quasi Normal Mode (QNM) approach for an open cavity is adopted, interpreting the local density of states (LDOS) as the local density of probability to excite one QNM of the ca…
Simulation of mid-IR amplification in Er3+-doped chalcogenide microstructured optical fiber
2009
International audience; This paper deals with the design of an erbium doped microstructured optical fiber (MOF) amplifier operating in the mid-infrared (mid-IR) wavelength range, more precisely around 4.5 µm wavelength. A homemade numerical code which solves the rate equations and the power propagation equations has been ad hoc developed to theoretically investigate the feasibility of mid-IR MOF amplifier. On the basis of the measured energy level transition parameters of a Er3+-doped Ga5Ge20Sb10S65 chalcogenide glass, the amplifier feasibility is demonstrated exhibiting high gain and low noise figure.