Fabrication and analysis of one-dimensional defect-induced ultrawide photonic band gaps

Title
Fabrication and analysis of one-dimensional defect-induced ultrawide photonic band gaps
Authors
Hwangbo, C.K.
Keywords
REFLECTOR, CRYSTAL, FILMS
Issue Date
2007-05
Publisher
AMER INST PHYSICS
Abstract
An approach named the defect-induced extension of photonic band gaps (PBGs) is proposed, in which a stratified periodic structure is combined with another stratified structure containing defect layers. For comparison, three structures composed of TiO2 and SiO2 alternating layers, perfect, five-defect and combined-photonic crystals (PCs), were fabricated by using an electron-beam evaporation system. The measured PBG width of combined-PCs extended to 370 nm at the normal incidence, nearly three times more than that of perfect ones, 130 nm, but a few ripples are observed within the PBG. In order to elucidate the origin of the ripples, the influence of the refractive-index contrast on the reflectance was analyzed theoretically. When the refractive-index contrast n(H)/n(L)>= 1.7, the ripples are eliminated. More importantly, an overdoubled omnidirectional PBG is realized at n(H)/n(L)=2.56, covering the visible region completely. This approach is considered to be based on the light localization and a heterostructure resulting from introducing the impurity band and compensating for it using PCs with a strictly periodic structure, in which the thickness of every layer remains unchanged. These characteristics distinguish it from other methods proposed before, with the fabrication much easier.
URI
http://dspace.inha.ac.kr/handle/10505/1664
ISSN
0021-8979
Appears in Collections:
College of Natural Science(자연과학대학) > Physics (물리학) > Journal Papers, Peports(물리학 학술논문, 보고서)
Files in This Item:
Fabrication.pdfDownload

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse