Application of Fiber Optic Surface Plasmon Resonance Sensor for Measuring Liquid Refractive Index

Abstract

An optical fiber sensor based on surface plasmon resonance (SPR) phenomenon that can be used for liquid refractive index testing is presented in this article. The effect of various parameters like the refractive index of the core and the liquid type on the shape of the SPR spectrum is analyzed, utilizing relative spectrum measurement technology. The relationship curves between several kinds of liquids with the same refractive index with their resonance wavelengths are also obtained using the sensing probe. Furthermore, experimental results of liquids with high refractive index reveal that the improved probe with SiO film has the ability to extend the detection upper limit of refractive index and keep the toughness of optical fiber at the same time.

Current status of micro- and nano-structured optical fiber sensors

“…This imposes a limitation in the sensing range of the refractive index. Hence, if a material that has higher refractive index than the core is overlayered, the sensing range of the refractive index can be changed to a higher level [40]. The same effect can also be achieved by using a different fiber core material that has a higher refractive index than a conventional optical fiber.…”

“…6 and Table 2. These include symmetrical structures, such as a simple metal coated optical fiber with and without remaining cladding [22][23][24][25][26][27], tapered fiber [28][29][30], structures without any symmetry, such as side-polished fibers (or D-shape fiber) and one-side metal coated fibers with and without remaining cladding [31][32][33][34][35][36][37][38], and structures with modified fiber tips with flat or angled structures [10,[39][40][41][42]. Each of them may contain either overlayer or multilayer structures.…”

“…Characteristics of general SPR-based fiber-optic sensors.• Multi-metal coating Au, Ag double layer, Au-Ag alloy nanoparticle ∼2500 ∼ 3000 nm/RIU[22] • With multi-layer MMF, Au, dielectric multilayer (SiO 2 , TiO 2 ) Ag end mirror, Ag coating, SiO layer 1.3365 and 1.4126, 1.4344 ∼ 1.5859 650 ∼ 1000 nm 3800 nm/RIU, 1000 nm/RIU[40] MMF, Ag end mirror, Au, Ag coating…”

Self-Calibration Highly Sensitive Photonic Crystal Fiber Biosensor

“…The calculated R-Square of the fitting lines of the sensitivities according to the quasi TE mode and quasi TM mode are equal to 0.96923 and 0.95974, respectively, and hence, high linearity can be obtained. Further, an average sensitivity of 12600 nm/RIU and 10080 nm/RIU can be achieved according to the quasi TE mode and quasi TM mode, respectively, which are larger than that of the PCF SPR biosensors reported in [5], [10]- [12], [14], [15], [21]- [23], as revealed from Table 1. Therefore, the proposed biosensor with high sensitivity and high linearity can be used as a self-calibration sensor within unknown analyte refractive index range from 1.33 to 1.35.…”

Overview of Micro- and Nano-Structured Surface Plasmon Resonance Fiber Sensors

“…The bending radius in U-shaped probe makes it possible to tune the sensitivity of the probe [17]. Furthermore, one-side metal coated fibers with and without remaining cladding, and structures with modified fiber tips such as flat or angled structures have been proposed [18,19]. Metal-coated length is a third of whole tapered length in step-index multimode fiber.…”