Open AccessDeep subwavelength confinement and threshold engineering in a coupled nanorods based spaser
Author(s) -
Mohammad Hossein Motavas,
Abbas Zarifkar
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.021579
Subject(s) - nanorod , nanolaser , materials science , plasmon , optoelectronics , optics , semiconductor , core (optical fiber) , fabrication , nanotechnology , lasing threshold , wavelength , physics , medicine , alternative medicine , pathology , composite material
In recent years, extensive efforts have been made for design and fabrication of low threshold spasers or plasmonic nanolasers at a deep subwavelength scale. Plasmonic nanolasers with coupled-nanorods structure can realize this purpose due to energy concentration in nano size volumes and effective amplification mechanisms. In this study, a group of structures based on metallic and CdS coupled nanorods are designed and analyzed using the finite element method (FEM). By changing the lateral adjacent surfaces of the metal and semiconductor nanorods through utilizing regular polygons as the cross sections of the nanorods, different characteristics of the plasmonic nanolaser are investigated. Simulation results show that the mode area normalized by the diffraction limit area is as low as 0.0062 in the structures based on hexagonal metallic core with circular semiconductor nanorods while structures based on circular Ag core with hexagonal CdS nanorods can provide a low threshold gain as 1.310 μm -1 . Also, it is shown that if ZnO be used as the semiconductor gain material instead of CdS, a normalized mode area of almost one tenth can be attained in a structure with dodecagonal metallic core and circular ZnO nanorods.