Sökning: "photonic band gaps"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden photonic band gaps.

1. 1. 3D Magnetic Photonic Crystals : Synthesis and Characterization

   Författare :Mei Fang; K.Venkat Rao; Lyubov Belova; Rajeev Ahuja; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; magnetic photonic crystals; photonic band gaps; Fe3O4 nanoparticles; silica; Optical physics; Optisk fysik; Materials science; Teknisk materialvetenskap;

   Sammanfattning : This thesis presents the synthesis methods and the characterizations of magnetic Fe3O4 nanoparticles, silica spheres with Fe3O4 nanoparticles embedded, and three dimensional magnetic photonic crystals (MPCs) prepared from the spheres. The structure, material composition, magnetic and optical properties, photonic band gaps (PBGs), as well as how these properties depend on the concentration of the magnetic nanoparticles, are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), superconducting quantum interference device (SQUID), Faraday rotation (FR) and optical spectrophotometers. LÄS MER

3. 2. Numerical Studies of Energy Gaps in Photonic Crystals

   Författare :Andreas Rung; Carl-Gustaf Ribbing; Norbert Kaiser; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; photonic crystals; polaritonic; periodic structures; Reststrahlen; band structure; energy gap; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Sammanfattning : The concept of photonic crystals was born in the late 1980's when two important letters were published that showed the possibility to control light propagation by a periodic structure. A photonic crystals consists of two or more materials with different dielectric functions periodically arranged on the length scale of light. LÄS MER

4. 3. Photonic crystals and photocatalysis : Study of titania inverse opals

   Författare :Delphine Misao Lebrun; Lars Österlund; Martyn Pemble; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; photocatalysis; titania; inverse opal; photonic crystal; optics; Teknisk fysik med inriktning mot fasta tillståndets fysik; Engineering Science with specialization in Solid State Physics;

   Sammanfattning : Due to an increase of human activity, an increase health risk has emerged from the presence of pollutants in the environment. In the transition to renewable and sustainable life style, treatment of pollutants could support the shifting societies. LÄS MER

5. 4. Technology and properties of InP-based photonic crystal structures and devices

   Författare :Naeem Shahid; Srinivasan Anand; Rob W. vad der Heijden; KTH; []
   Nyckelord :Integrated optics materials; Photonic crystals; Planar waveguides; Dispersion; Band-gap; Mode-gap; mini-stopband; InP; Nanostructure fabrication; dry etching; mass transport; material reflow; reliability; SRA - ICT; SRA - Informations- och kommunikationsteknik;

   Sammanfattning : Photonic crystals (PhCs) are periodic dielectric structures that exhibit a photonic band gap; a range of wavelengths for which light propagation is forbidden. 2D PhCs exhibit most of the properties as their three dimension counterparts with a compatibility with standard semiconductor processing techniques such as epitaxial growth, electron beam lithography, Plasma deposition/etching and electromechanical lapping/polishing. LÄS MER

7. 5. Optical properties of active photonic materials

   Författare :Yong Zeng; Ying Fu; Philip Russell; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nanophotonics; plasmonics; Theoretical chemistry; Teoretisk kemi;

   Sammanfattning : Because of the generation of polaritons, which are quasiparticles possessing the characteristics of both photonics and electronics, active photonic materials offer a possible solution to transfer electromagnetic energy below the diffraction limit and further increase the density of photonic integrated circuits. A theoretical investigation of these exciting materials is, therefore, very important for practical applications. LÄS MER