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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A5B6C7 tipo kristalų paprastojo grafo ypatumai / A5B6C7 type crystals graph singularity

Kučinskas, Evaldas 12 June 2006 (has links)
A5B6C7 type crystals are semiconductors – paraelectronics. I analysed this crystal structure and compared free methods of investigation.
2

Elektromagnetinių bangų sklidimas fotoniniuose kristaluose / Electromagnetic waves propagation in photonic crystals

Kulbickas, Augustinas 14 June 2005 (has links)
Recently photonic crystals with a three - dimensional ordered structure with periodicity of the optical wavelength have attracted attention from both fundamental and practical points of view. Control of electromagnetic waves flow in photonic crystals was discussed. The application of photonic crystals is to create tunable band gap materials especially in visible spectra region, where the gap could be controlled by an external parameter. Opal crystal films have been fabricated on solid substrates with a horizontal deposition method. We have studied transmission spectra of synthetic opal, infiltrated with nematic liquid crystal 5CB and demonstrating that the position of the stop band in the visible spectra is shifted to IR wavelength with increasing volume part of 5CB in photonic crystal opal. We show dependence upon stop band position and light incidence angle in bare opal. It is a possibility turning this stop band. Opal filled with LC photonic strength was studied. We demonstrating that photonic strength saturates when was filled about 20% of opal voids.
3

Optinės informacijos užrašymas fotoniniame kristale, sukuriant defektus / Optical information storage in defected photonic crystal

Janavičius, Paulius 15 June 2005 (has links)
We have studied inverse opal optical properties. Defects, action on photonic band gab position was discussed. We showed that defect gives us possibility to control light flow in photonic crystal.
4

Krūvininkų generacija SbSI kristaluose / Charge transfer in SbSI crystals

Budėnas, Marius 16 June 2005 (has links)
Metal-to-semiconductor contacts are of great importance since they are present in every semiconductor device. Charge transfer in SbSI crystals was discussed. We have studied current strength-voltage and current strength-temperature characteristics of Schottky barrier metal-semiconductor contacts to Ag/SbSI/Ag and Al/SbSI/Al.
5

SbSI IR SbSeI kristalų fotoelektroniniai spektrai, jų aproksimacija ir analizė / Interpretation of SbSI and SbSeI crystals

Nelkinas, Viačeslavas 13 June 2005 (has links)
The photoionization enegies and electronic structure of the valence band (VB) of SbSI crystal can be calculated by solving the Hartree-Fock-Roothan matrix equation FC=SCε where the diagonal matrix ε gives the electron state energies. These energies experimentally are studied in a wide temperature range by PHI 5700/660 Physical Electronics Spectrometer using excitation source Al Ka monochromatic radiation (1486.6 eV). The photoelectron spectra were measured in the energy range 0 - 1450 eV.
6

Šviesos valdymas nanofotoniniame kristale / Light flow control in photonic crystals

Balcevičius, Ričardas 15 June 2005 (has links)
Recently photonic crystals with a three - dimensional ordered structure with periodicity of the optical wavelength have attracted attention from both fundamental and practical points of view.Light flow control in photonic crystals was discussed.Opal crystal films have been fabricated on solid substrates with a vertical deposition method.
7

Hibridinių fotoninių kristalų optinės savybės / Optical features of hybrid photonic crystals

Rastenienė , Loreta 24 September 2008 (has links)
Paskutiniais dešimtmečiais puslaidininkių fizika vaidino svarbų vaidmenį beveik kiekvienoje šiuolaikinių technologijų srityje. Šiame greitai besikeičiančiame pasaulyje mūsų jau nebetenkina supantys buities ir darbo prietaisai, valdomi naudojantis elektronais. Mums reikalingas didesnis kompiuterių operatyvumas, didesnė atminties talpa, greitesnis telekomunikacinis ryšys, ir todėl reikalingos naujos technologijos bei sprendimai. Naujas žingsnis fotoninės struktūros. Žinių ir technologijų pasiekimai leidžia fotoninių sturktūrų savybes taikyti šviesos valdymui. Dabartiniame optinės fizikos tyrinėjimų etape šviesos sąveika su medžiaga labai aktuali: ji gali atrodyti universali ir invariantiška, kadangi šviesa jau kontroliuojama pasitelkus hibridinius fotoninius kristalus. Šių darinių tyrimai patrauklūs tiek fundamentaliam, tiek taikomajam mokslui. Į opalą infiltravę skystąjį kristalą, gauname hibridinį fotoninį kristalą. Jo optines savybes galima keisti priklausomai nuo infiltruotos medžiagos lūžio rodiklio. Fotoniniai kristalai, reikia tikėtis, bus taikomi ateities fotoniniuose įrenginiuose, telekomunikacijoje. Su šia sritimi siejamos tokios pat ar net didesnės viltys, kokios buvo siejamos su prieš 50 metų išrastu puslaidininkiniu tranzistoriumi, pakeitusiu techniką ir davusiu impulsą naujoms mokslo kryptims. Teoriškai fotoninių kristalų egzistavimą nepriklausomai vienas nuo kito 1987 metais pirmieji aprašė E.Jablonovičius ir S. Johnas. Tačiau prireikė dar dešimt metų, kol buvo... [toliau žr. visą tekstą] / We live in the rapidly developing technological world. However, fields of communication, computer memory, and data processing require considerable improvements. The speed of data transportation is acceptable but capacity is low. There is a growing need for new technologies that rapidly detect and treat diseases at an early stage or even pre-stage. When we get accustomed to the advance, we demand more compact, energy-efficient, rapidly-responding and environmentally-safe technologies. During the last century this problem was solved by switching to transportation of electronic data, which connected people around the world. This approach had changed our lives, but about twenty years ago this technology reached its limits, while need for an even higher transportation capacity increases. Now we need faster computers and other state-of-the-art technological solutions: electrons are too slow and we have to use photons. Over the last decade, the steady progress regarding ability to fabricate hybrid photonic nanostructures led to a rich variety of different one-, two-, and three-dimensional dielectric/organic and/or metallic periodic structures. They demonstrate qualitatively new and fascinating linear-optical, nonlinear-optical, and quantum-optical features which provide an unprecedented control of light propagation and light-matter interaction. Photonic-based technology, coupled with nanotechnology, can meet many of these challenges. In this work fabrication of hybrid photonic... [to full text]
8

Nanomagnetinės dalelės fotoniniame kristale / Nanomagnetic particles in photonic crystals

Mikšys, Mantas 13 June 2005 (has links)
In this paper we outline a new direction in the area of photonic crystals, or photonic band gap materials,one-, two-, or three-dimensional superstructures with periods that are comparable with the wavelengths of electromagnetic radiation. The main characteristic of this new class of PCs is the presence of magnetically ordered components. The linear and nonlinear optical properties of such magnetic PCs are discussed.
9

Hibridinių fotoninių kristalų optinės savybės / Optical features of hybrid photonic crystals

Rastenienė , Loreta 24 September 2008 (has links)
Paskutiniais dešimtmečiais puslaidininkių fizika vaidino svarbų vaidmenį beveik kiekvienoje šiuolaikinių technologijų srityje. Šiame greitai besikeičiančiame pasaulyje mūsų jau nebetenkina supantys buities ir darbo prietaisai, valdomi naudojantis elektronais. Mums reikalingas didesnis kompiuterių operatyvumas, didesnė atminties talpa, greitesnis telekomunikacinis ryšys, ir todėl reikalingos naujos technologijos bei sprendimai. Naujas žingsnis fotoninės struktūros. Žinių ir technologijų pasiekimai leidžia fotoninių sturktūrų savybes taikyti šviesos valdymui. Dabartiniame optinės fizikos tyrinėjimų etape šviesos sąveika su medžiaga labai aktuali: ji gali atrodyti universali ir invariantiška, kadangi šviesa jau kontroliuojama pasitelkus hibridinius fotoninius kristalus. Šių darinių tyrimai patrauklūs tiek fundamentaliam, tiek taikomajam mokslui. Į opalą infiltravę skystąjį kristalą, gauname hibridinį fotoninį kristalą. Jo optines savybes galima keisti priklausomai nuo infiltruotos medžiagos lūžio rodiklio. Fotoniniai kristalai, reikia tikėtis, bus taikomi ateities fotoniniuose įrenginiuose, telekomunikacijoje. Su šia sritimi siejamos tokios pat ar net didesnės viltys, kokios buvo siejamos su prieš 50 metų išrastu puslaidininkiniu tranzistoriumi, pakeitusiu techniką ir davusiu impulsą naujoms mokslo kryptims. Teoriškai fotoninių kristalų egzistavimą nepriklausomai vienas nuo kito 1987 metais pirmieji aprašė E.Jablonovičius ir S. Johnas. Tačiau prireikė dar dešimt metų, kol buvo... [toliau žr. visą tekstą] / We live in the rapidly developing technological world. However, fields of communication, computer memory, and data processing require considerable improvements. The speed of data transportation is acceptable but capacity is low. There is a growing need for new technologies that rapidly detect and treat diseases at an early stage or even pre-stage. When we get accustomed to the advance, we demand more compact, energy-efficient, rapidly-responding and environmentally-safe technologies. During the last century this problem was solved by switching to transportation of electronic data, which connected people around the world. This approach had changed our lives, but about twenty years ago this technology reached its limits, while need for an even higher transportation capacity increases. Now we need faster computers and other state-of-the-art technological solutions: electrons are too slow and we have to use photons. Over the last decade, the steady progress regarding ability to fabricate hybrid photonic nanostructures led to a rich variety of different one-, two-, and three-dimensional dielectric/organic and/or metallic periodic structures. They demonstrate qualitatively new and fascinating linear-optical, nonlinear-optical, and quantum-optical features which provide an unprecedented control of light propagation and light-matter interaction. Photonic-based technology, coupled with nanotechnology, can meet many of these challenges. In this work fabrication of hybrid photonic... [to full text]
10

Šviesos sklidimo vienaašiuose optiniuose kristaluose teorinis tyrimas / Light propogation in uniaxial cristals teoretical research

Mockaitis, Artūras 15 June 2005 (has links)
Light propogation in uniaxial crystal was discussed. We used Maxvel equations for electromagnetic waves in vectorial form and general environment equations for liquid crystals to deduced Frenel equation. We make study of tetragonal singony planar class liquid crystal.

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