Mixed plasmons coupling for expanding the bandwidth of near-perfect absorption at visible frequencies.
We theoretically investigate the electromagnetic response of mixed-size sub-wavelength square hole array (M-SHA) combined with thick metal layer (TML). Near-perfect absorption with bandwidth about 17 nm is firstly observed. Field distribution and dispersion relationship indicate that mixed surface plasmons (M-SPs) coupling is supported by M-SHA and TML. The absorption band is proved to be dominated by M-SPs coupling.
Hu
Chenggang
C
State Key Laboratory of Optical Technologies for Microfabrication, Institute of Optics and Electronics, Chinese Academy of Sciences, P.O. Box 350, Chengdu 610209, China.
Liu
Liyuan
L
Zhao
Zeyu
Z
Chen
Xu'nan
X
Luo
Xiangang
X