SCIENTIfIC REPORTS | 7: 16817 | DOI:10.1038/s41598-017-17024-7
Simultaneous realization of high
sensing sensitivity and tunability in
plasmonic nanostructures arrays
Yuan-Fong Chou Chau
, Chan-Kuang Wang
, Linfang Shen
, Chee Ming Lim
, Chung-Ting Chou Chao
, Hung Ji Huang
, Chun-Ting Lin
, N. T. R. N. Kumara
Nyuk Yoong Voo
A plasmonic nanostructure (PNS) which integrates metallic and dielectric media within a single
structure has been shown to exhibit specic plasmonic properties which are considered useful in
refractive index (RI) sensor applications. In this paper, the simultaneous realization of sensitivity and
tunability of the optical properties of PNSs consisting of alternative Ag and dielectric of nanosphere/
nanorod array have been proposed and compared by using three-dimensional nite element method.
The proposed system can support plasmonic hybrid modes and the localized surface plasmonic
resonances and cavity plasmonic resonances within the individual PNS can be excited by the incident
light. The proposed PNSs can be operated as RI sensor with a sensitivity of 500 nm/RIU (RIU = refractive
index unit) ranging from UV to the near-infrared. In addition, a narrow bandwidth and nearly zero
transmittance along with a high absorptance can be achieved by a denser PNSs conguration in the unit
cell of PNS arrays. We have demonstrated the number of modes sustained in the PNS system, as well
as, the near-eld distribution can be tailored by the dielectric media in PNSs.
Surface plasmon resonance (SPR) produced by the collective oscillations of free electrons at resonance wave-
) occurs in plasmonic nanoparticles (NPs) when these NPs are exposed to light from the ultraviolet
(UV) to the near-infrared
. In the various studies to nd applications of SPR, metal nanoparticle (MNP) arrays
have been shown to have diverse applications because of their ability to give rise to enhanced local electromag-
netic (EM) waves within a sub-wavelength nanometer-sized scale
. In periodic MNP conguration, the SPRs
can be excited at the interface between the MNPs and the dielectric media, when the energy and momentum of
the incident light match that of the SP waves
. e application of MNP array is a rapidly developing area, and
the use of MNP arrays have been demonstrated in elds ranging from information processing, communication
to quantum optics and bioscience
Plasmonic nanostructures (PNSs) are used to describe the combination of structured metallic and dielectric
media formed within a single structure. is combination is oen found to be useful because light can localized
at the metal-dielectric interfaces. e localization of light exhibits many novel properties that are unattainable
in nanostructures of a single material
. One important novel property found in metal-dielectric combinations
is the strong plasmon-exciton coupling, and the nonlinear optical response can, when combined, produces new
physical behaviors on one hand, and in the other hand gives more controlled capabilities via the tuning of the
dielectric medium of the PNSs. e tuning occurs through the manipulation of the SPs by the changing of the
It is well known that refractive index (RI) sensors having extraordinarily high spectral sensitivity can be
achieved using SPR modes
. e enhancement and connement of light by plasmonics allows a high
density of independent subwavelength sensor elements to be formed in the periodic MNP arrays of RI sensors.
Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong, BE1410,
Negara Brunei Darussalam.
Department of Electronic Engineering, Chien Hsin University of Science and Technology,
No. 229, Jianxing Rd., Zhongli City, Taoyuan County, 32097, Taiwan (R.O.C.).
Institute of Space Science and
Technology, Nanchang University, Nanchang, 330031, China.
Institute of Optoelectronic Sciences, National Taiwan
Ocean University, No. 2 Pei-Ning Rd., 202, Keelung, Taiwan.
Institute of Physics, Academia Sinica, Taipei, Taiwan.
Department of Physics, Fu Jen Catholic University, New Taipei City, Taiwan.
Instrument Technology Research
Center, National Applied Research Laboratories, Hsinchu, Taiwan. Correspondence and requests for materials should
be addressed to Y.-F.C.C. (email: firstname.lastname@example.org) or H.-P.C. (email: email@example.com)
Received: 21 June 2017
Accepted: 21 November 2017
Published: xx xx xxxx