Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  discrete diffraction
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote Tunability of discrete diffraction in photonic liquid crystal fibres
EN
In this paper theoretical and experimental results regarding discrete light propagation in photonic liquid crystal fibres (PLCFs) are presented. Particular interest is focused on tunability of the beam guidance obtained due to the variation in either external temperature or optical power (with assumption of thermal nonlinearity taking place in liquid crystals). Highly tunable (discrete) diffraction and thermal self-(de)focusing are studied and tested in experimental conditions. Specifically, spatial light localization and/or delocalization due to the change in tuning parameters are demonstrated, with possibility of discrete spatial (gap) soliton propagation in particular conditions. Results of numerical simulations (performed for the Gaussian beams of different widths and wavelengths) have been compared to those from experimental tests performed in the PLCFs of interest. Owning to the limit of experimental means, direct qualitative comparison was not quite accessible. Nevertheless, a qualitative agreement between theoretical and experimental data (obtained in analogous conditions) has been achieved, suggesting a compact and widely-accessible platform for the study of tunable linear (and nonlinear) discrete light propagation in two-dimensional systems. Proposed photonic structures are of a great potential for all-optical beam shaping and switching.
EN
We investigate linear and nonlinear light propagation in the photonic crystal fibers infiltrated with nematic liquid crystals. Such a photonic structure, with periodic modulation of refractive index, which could be additionally controlled by the temperature and by the optical power, allows for the study of discrete optical phenomena. Our theoretical investigations, carried out with the near infrared wavelength of 830 nm, for both focusing and defocusing Kerr-type nonlinearity, show the possibility of the transverse light localization, which can result in the discrete soliton generation. In addition, we present the preliminary experimental results on the linear light propagation in the photonic crystal fiber with the glycerin-water solution and 6CHBT nematics, as the guest materials.
3
Content available remote Nematic liquid crystal waveguide arrays
EN
We investigate linear and nonlinear light propagation in a voltage-tunable array of waveguide channels in undoped nematic liquid crystals. This novel geometry, based on a photonic structure with a periodic modulation of refractive index controlled by an electric field, offers a wealth of possibilities for the study of discrete optical phenomena. The structure, in conjunction with a giant, non-resonant and voltage-dependent reorientational nonlinearity, allows us to drive the system from bulk diffraction to discrete propagation. Theoretical and experimental investigations, carried out with near infrared light wavelength and powers of a few milliWatts, show the possibility of transverse light localization, resulting in discrete spatial solitons. Such array, with its voltage- and light-adjustable guided-wave confinement and coupling, exhibits potentials for the realization of multifunctional routers and all-optical signal processors with nematic liquid crystals.
EN
Propagation of light in an optically induced waveguide array in biased photorefractive media with a quadratic electro-optic effect is investigated numerically with the beam propagation method. The refractive index distribution of the array is induced by two coherent plane waves interfering in a guiding layer in a photorefractive multiple quantum well (MQW) planar waveguide. The influence of modulation depth and the space period of an interference pattern as well as the external electric field intensity on diffraction properties of the array is analysed. The potential possibility of all-optical switching due to the dependence of the guided wave output distribution on the external waves parameters is shown.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.