Wyniki wyszukiwania - Biblioteka Nauki

1

Photonic crystals: a novel class of functional materials

100%

Modinos A. , Stefanou N.

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tom Vol. 23, No. 4

877--881

EN

Photonic crystals are inhomogeneous materials whose dielectric properties vary periodically in space on a macroscopic scale. These materials have novel and interesting properties concerning both basic physics and technological applications. After a brief description of the main properties of photonic crystals, we present some specific applications related to wave guiding and Anderson localization of light due to stacking faults in these crystals.

2

Optical gain in one-dimensional photonic band gap structures with n-i-p-i crystal layers

100%

Nefedov I. S. , Gusyatnikov V. N. , Marciniak M. , Kononenko V. K. , Ushakov D. V.

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tom nr 1

60-64

EN

The gain enhancement in a layered periodic photonic band gap structure containing active medium based on GaAs n-i-p-i superlattices separated by A1GaAs layers is analyzed. The dependences of extinction coefficient and refractive index on excitation level and wavelength are presented. Transmission characteristics of a probe light versus excitation level are calculated. It is shown that the threshold of generation can be essentially reduced if the wavelength of probe light falls to the band gap edge.

3

A Photonic-Crystal Selective Filter

88%

Pajewski L. , Schettini G.

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2017

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tom nr 3

107--112

EN

A highly selective filter is designed, working at 1.55 μm and having a 3-dB bandwidth narrower than 0.4 nm, as is required in Dense Wavelength Division Multiplexed systems. Different solutions are proposed, involving photonic crystals made rectangular- or circular-section dielectric rods, or else of holes drilled in a dielectric bulk. The polarization and frequency selective properties are achieved by introducing a defect in the periodic structure. The device is studied by using in-house codes implementing the full-wave Fourier Modal Method. Practical guidelines about advantages and limits of the investigated solutions are given.

4

Dwuwymiarowe kryształy fotoniczne jako materiał nowoczesnej fotoniki : metody wytwarzania i zastosowania

75%

Lis S. , Ptasiński K. , Ryba P. , Wielichowski M. , Zakrzewski A. , Patela S.

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tom Vol. 53, nr 2

29-32

PL

Kryształy fotoniczne to sztucznie wytwarzane struktury, które mogą pełnić rolę materiału bazowego do budowy elementów fotoniki. W pracy omówiono jedną z metod wytwarzania kryształów fotonicznych - tak zwaną litografię interferencyjną. Następnie przeanalizowano możliwość wykorzystania struktur kryształu fotonicznego do budowy optycznego czujnika gazów.

EN

Photonic crystal is an artificially fabricated structure, that can serve as a base material for production of photonic elements. In this paper one of the methods of photonic crystal fabrication - so called interference lithography - is presented. Further, possibility of application of the photonic crystal for design of optical gas sensor is analyzed.

5

Interferential polychromatic filters based on the quasi-periodic one-dimensional generalized multilayer Thue - Morse structures

75%

Bouazzi Y. , Kanzari M.

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2009

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tom Vol. 39, nr 3

489-498

EN

In this paper, a new type of optical filter using photonic band gap materials has been proposed. The optical filter was obtained by a combination of periodic H(LH)J and generalized Thue - Morse (GTM) quasi-periodic one-dimensional multilayer. We show that the whole structure H(LH)J[TM]PH(LH)J, where P is the repetition number of the GTM stack, has an interesting application as a polychromatic filter. However, the effect of the repetition number for producing an improved polychromatic filter is presented. So, switches like (on-on-off-off-on-on-…) have been found.

6

Guided modes in capillary optical fibers

51%

Romaniuk R. S.

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2008

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tom Vol. 54, No 3

323-342

EN

A comparatively large group of capillary optical fibers, referred to in this paper as COF, consists of several families of optical filaments. The basic division line goes through the wave guidance mechanism. Two basic kinds of capillary optical fibers are of refractive and photonic mechanism of guided wave transmission. The work tries to compare wave modes in both kinds of optical fiber capillaries: refractive (RCOF) and photonic (PCOF). The differences are emphasized indicating prospective application areas of these fibers. Refractive COF carries most of the modal light in the ring-like, high-refraction, optical glass core encircling an empty capillary hole. Refractive capillary optical fibers are used widely for photonic instrumentation applications, due to the proximity of optical wave and capillary hole with the evanescent wave. The hole can be filled with a material subject to optical guided wave spectrometry. Photonic COF carries most of the light in air (or vacuum). Thus, photonic capillary optical fibers are considered for trunk optical communications, with guided wave travelling in vacuum rather than in glass - avoiding in this way the Rayleigh scattering. The fundamental mode in a refractive COF is LPoi or dark hollow beam (DHB) of light with zero intensity on fiber axis. The fundamental mode in a photonic COF is Gaussian beam with maximum intensity on fiber axis. The photonic COFs can be further divided to two basic groups: porous or holey/hollow and Bragg or OmniGuide fibers. These two kinds of PCOFs differ by the method of building a photonic band gap (PBG) around a capillary hole. The paper is a concise digest of fundamental kinds of singlemode (or low-order mode) COFs and their properties, with an emphasis on applications in two basic fields: instrumentation and telecommunications.