Surface plasmon resonance biosensor based on gold-coated side-polished hexagonal structure photonic crystal fiber

Abstract

The refractive index sensing characteristics of the side-polished photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor are detailed investigated in this paper. We used the finite element method (FEM) to study the influences of the side-polished depth, air hole size, lattice constant, and the refractive index (RI) of the PCF material on sensing performance. The simulation results show that the side-polished depth, air hole size, lattice pitch have significant influence on the coupling strength between core mode and surface plasmon polaritons (SPPs), but have little influence on sensitivity; the coupling strength and sensitivity will significant increase with the decrease of RI of the PCF material. The sensitivity of the D-shaped PCF sensor is obtained to be as high as 21700 nm/RIU in the refractive index environment of 1.33-1.34, when the RI of the PCF material is controlled at 1.36. It revealed a new method of making ultra-high sensitivity SPR fiber sensor. Then we experimental demonstrated a SPR refractive sensor based on the side-polished single mode PCF and investigated the sensing performance. The experimental results of the plasmon resonance wavelength sensitivity agree well with the theoretical results. The presented gold-coated D-shaped PCF SPR sensor could be used as a simple, cost-effective, high sensitivity device in bio-chemical detection.

Dual-Core Photonic Crystal Fiber Plasmonic Refractive Index Sensor: A Numerical Analysis

“…For example, a PCF-SPR biosensor for the low refractive index (RI) detection was proposed by Liu et al [9] with low spectral sensitivity and amplitude sensitivity of 6000 nm/RIU and 600 RIU −1 , respectively. In the same fashion, side-polished hexagonal structured D-shaped PCF-SPR biosensor was demonstrated by Tiesheng et al [10] with the excellent value of wavelength sensitivity (21 700 nm/RIU) without considering amplitude sensitivity which is a very important term for characterizing the SPR sensor. Moreover, highly sensitive SPR biosensors were reported that focused on the high spectral sensitivity rather than considering amplitude sensitivity [11,12].…”

Highly sensitive surface plasmon resonance biosensor based on a low-index polymer optical fiber

“…3(b) with black solid squares and the sensitivities are labeled nearby with black numbers. The nonlinearity of sensitivity enhancement is mainly determined by the dispersion characteristics of SP mode at the metal/analyte interface, which is also demonstrated with silica fiber based SPR sensors [14,15]. It should be noted that the full-width at half-maximum (FWHM) of the SPR resonant dip broadens with the resonant dip shifts to longer wavelengths, which will degrade the figure of merit (FOM) of the device.…”

“…Of course, there are still rooms to enhance the FOM, such as using a single mode POF with similar materials to decrease the FWHM of SPR resonant dips. We simulated and analyzed the mode coupling properties and RI response of the proposed sensor by the finite element method [10,15,22]. The model was established according to the sensor geometry shown in the top-left inset of Fig.…”

“…Since the first demonstration of fiber optic SPR sensors [7], numerous designs have been proposed for SPR sensing with modified sensitivities and/or detection limits, mainly employing single mode fibers (SMFs) and multimode fibers (MMFs) accompanied with side-polishing [8][9][10], chemical-etching [11,12] and tapering-down treatments [13]. Recently, the diversity of optical fibers, such as D-type fibers [14], photonic crystal fibers [15,16], twin-core fibers [17], and two mode fiber [18], also enriches the forms of SPR sensors. And a high sensitivity of 6463 nm/RIU (refractive index unit) has been reported for aqueous solution test with an end-face grinded twin-core fiber SPR sensor [17].…”

Surface plasmon resonance refractive index sensor based on fiber-interface waveguide inscribed by femtosecond laser

“…To simulate the mode characteristics of the fiber interfacewaveguide SPR sensor, we use the finite element method with perfect match layers (PMLs) boundaries [3], and the simulation is carried out by COMSOL Multiphysics [13]. The simulated model is established based on the device size in Fig.…”