A surface plasmon resonance (SPR) sensor hybridized with self-assembled metallic nanoparticles is proposed and experimentally demonstrated. The measured sensitivity of the proposed SPR sensor is 110.77 deg/RIU, while that of a conventional SPR sensor is 84.75 deg/RIU. The enhanced sensitivity is attributed to the strong localized surface plasmons and the increased surface interaction area by the nanoparticles. Angle variation measurement, which is an easy detection method using bulk optics, is possible with this structure because a supplementary metallic thin film layer on the nanoparticles leads to utilization of the sensitive variation of the strong localized field by the change of the refractive index. Furthermore, the proposed structure can be fabricated with a very simple three-step nonlithographic process.
In this paper, we propose a surface plasmon resonance (SPR) sensor with metallic nano-particles, which is based on the
Kretschmann configuration for reflective-type measurement with enhanced sensitivity. The proposed structure is
analyzed and compared with a conventional Kretschmann configuration by using 3D finite-difference time-domain
method. The proposed structure is composed of semi-spherical nano-particles and a thin cladding layer. The evanescent
field on the metallic structure is enhanced by the factor of 2.7, where the diameter of nano-particles, fill factor, and
thickness of cladding film layer TF are 30 nm, 50 %, and 40 nm, respectively. On the other hand, the enhancement of the evanescent field in the conventional SPR sensor is 1.7 for the same TF. Because of the enhanced evanescent field, the
sensitivity of our proposed sensor is maximized to 137.1 degree/RIU while that of a conventional SPR sensor is 99.6
degree/RIU.
A novel polarization rotator with asymmetric optical waveguide based on plasmonics is proposed and analyzed for the
first time. The polarization rotator using skewing effects at the slotted optical waveguide (SOW) with metal film was
designed by 3D-FDTD method. A metal film on the waveguide acts to rapidly rotate the optical polarization, because the plasmonic characteristics of a metal film can induce the slow group velocity through the metal-clad optical waveguide. Here, the optical waveguide with a buffer layer is proposed to reduce the propagation loss. The polarization rotator length of 6 μm is among the shortest reported in the waveguide-type polarization rotators. The polarization conversion efficiency of 98.93 % is observed near 1550 nm along with a propagation loss of -0.43 dB. The proposed structure is smaller than previous polarization rotator with asymmetric optical waveguide and is more effective to control polarizations using by plasmonic effects.
In this paper, we have designed and optimized the metallic nano-structures on a conventional surface plasmon resonance (SPR) sensor which induce the localized surface plasmon resonance for an improved sensitivity. Designed SPR sensor was simulated with 3D Finite-difference time-domain method. The sensitivity is maximized to 130.9 degree/RIU when the thickness of film layer TF is 30 nm while that of a conventional SPR sensor is less than 99.6 degree/RIU, and the reflectivity is minimized when TF is 25 nm. The most appropriated diameter of particles is about 35 nm for high sensitivity.
We introduce an ultra-sensitive integrated photonic sensor structure using silicon on insulator based triangular resonator, in which a surface plasmon resonance (SPR) gold film is applied on a total internal reflection mirror. We have analyzed and optimized the triangular resonator sensor structure with an extremely small SPR mirror sensing area. Due to the large phase shift in the SPR mirror, a significantly enhanced sensitivity of 800 nm/RIU (refractive index unit) and the maximum peak shift of half free spectral range have been obtained at the SPR angle of 22.65° with Au thickness of 35 nm for the change of the refractive index Δn = 1x10-3.
In this paper, we have theoretically analyzed and designed a 1D PhC microcavity sensor with SPR based on the total
internal reflection mirror using analytic calculation and FDTD methods. The proposed structure has many advantages.
One of that is a high sensitivity using SPR characteristics. Another is a high Q-factor of the characteristics in the PhC
microcavity structure. The incident light has double resonance characteristics, because the filtered light by PhC structure
is met the thin metal film for SPR effect. We have also observed the change of resonance characteristics according to the
variation of effective index on the metal film.
In this paper, we have demonstrated a metallic nano-structured SPR sensor for an improvement of biosensing
sensitivity using a metallic nano-structure. Permittivity of metal is calculated with Drude model for analysis. The
sensitivity of SPR sensor with metallic nano-structure is 65 degree/RIU, and that of conventional SPR configuration is
54.8 degree/RIU. We have fabricated the random metallic nano-structures on the metallic thin film using the RIE etching
process. Moreover, we have analyzed the structure using the finite-difference time-domain method for the exact
characteristic.
An integrated surface plasmon resonance (SPR) array sensor using wideband sources and a different incident angle
with a single fluidic channel in order to increase the sensitivity is proposed and analyzed. The SPR reflectance was
analyzed using the finite-difference time-domain gaussian source method. The maximum difference is shown at the
incident angle of 24.6°. The sensitivity of the resonance shift used to change the refractive index of 1x10-3 is 51000
nm/RIU at the wavelength interrogation. The extremely small integrated SPR array sensor is a very attractive
component because of its promise of a high level of sensitivity, its easy measurement process, and its ease of integration
into a sensor system.
Recently, the bending efficiency of vertical slot waveguide with different structure has been analyzed. However, the
interface roughness of the waveguide which have high E-field intensity induces to high scattering loss. In addition, a
vertical slot fabrication involves in a very narrow region etching which can cause large roughness in the vertical
interfaces. In order to reduce the propagation loss and facilitate the fabrication process, horizontal slot waveguides have
been proposed and fabricated, recently. In this paper, we have designed and analyzed total internal reflection (TIR)
mirror for using a resonator based on horizontal slot waveguide. Our proposed structure is consisted horizontal slot
waveguide of rib type to enlarge contact region with TIR mirror. To analyze Goos-Hänchen shift, we have theoretically
calculated length of evanescent field at TIR mirror using 3D-FDTD method. The presented TIR mirror loss analysis can
be applied to enhance the efficiency of horizontal slot waveguide resonator which can potentially be used in many
silicon based optoelectronic devices.
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