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Tapered N-helical metamaterials with three-fold rotational symmetry as improved circular polarizers

Kaschke, J.; Blome, M.; Burger, S.; Wegener, M.

Abstract:
Chiral helix-based metamaterials can potentially serve as compact and broadband circular polarizers. We have recently shown that the physics of structures composed of multiple intertwined helices, so called N-helices with N being an integer multiple of 4, is distinct from that of structures made of single circular helices (N = 1). In particular, undesired circular polarization conversion is strictly eliminated for N = 4 helices arranged on a square lattice. However, the fabrication of such structures for infrared/visible operation wavelengths still poses very significant challenges. Thus, we here revisit the possibility of reducing N from 4 to 3, which would ease micro-fabrication considerably. We show analytically that N = 3 helices arranged on a hexagonal lattice exhibit strictly vanishing circular polarization conversion. N = 3 is the smallest option as N = 2 obviously leads to linear birefringence. To additionally improve the circular-polarizer operation bandwidth and the extinction ratio while maintaining high transmission for the wanted polarization and zero conversion, we also investigate by numerical calculations N = 3 helices with tapered diameter along the helix axis. ... mehr

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Volltext §
DOI: 10.5445/IR/1000043556
Originalveröffentlichung
DOI: 10.1364/OE.22.019936
Scopus
Zitationen: 32
Web of Science
Zitationen: 30
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Physik (APH)
Institut für Nanotechnologie (INT)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2014
Sprache Englisch
Identifikator ISSN: 1094-4087
urn:nbn:de:swb:90-435563
KITopen-ID: 1000043556
HGF-Programm 43.14.01 (POF II, LK 01)
Photonics crystals and metamaterials
Erschienen in Optics Express
Band 22
Heft 17
Seiten 19936-19946
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Nachgewiesen in Web of Science
Scopus
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