13 July 2017 Period- and cavity-depth-dependent plasmonic metamaterial perfect absorber at visible frequency: design rule
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Abstract
Plasmonic perfect absorbers are artificially designed metal-dielectric-metal (MDM) structures to realize unity optical absorption (UOA) at the specific spectral wavelength. In the recent past, a variety of structures have been investigated theoretically and experimentally to achieve UOA. However, fabrication of a complex structure often requires sophisticated instruments and skills. A simple structural design may be an alternative solution. An MDM structure consisting of a square array of cylindrical holes in the top layer is proposed, and optical reflection/absorption is studied using 3-D finite-difference time-domain computation to achieve UOA. The structure has three sequential layers: a ground gold plane (100-nm thick) to block the transmission, a spacer layer of typical thickness of 20 nm of constant real value of dielectric permittivity, and a top gold layer structured with periodic square array of cylindrical holes. Numerical results show period- and hole-depth-dependent 100% optical absorption (UOA) at a specific spectral wavelength. A significant influence of hole packing density and refractive index of filled material on the resonant absorption and absorption bandwidth is also observed. Based on the results, a design rule is proposed to achieve UOA at an arbitrarily chosen spectral wavelength in the visible range.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Prasanta Mandal, Prasanta Mandal, Ch. Nageswar Rao, Ch. Nageswar Rao, } "Period- and cavity-depth-dependent plasmonic metamaterial perfect absorber at visible frequency: design rule," Journal of Nanophotonics 11(3), 036003 (13 July 2017). https://doi.org/10.1117/1.JNP.11.036003 . Submission: Received: 4 March 2017; Accepted: 20 June 2017
Received: 4 March 2017; Accepted: 20 June 2017; Published: 13 July 2017
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