Search

This work elucidates the numerical simulations carried out for the performance analysis of surface plasmon resonance (SPR)–based fiber-optic sensors using thin layers of tantalum (v) oxide (Ta2O5) and graphene in phase interrogation scheme. For this purpose, fiber-optic sensing probes with three distinct configurations have been used which include consecutive as well as individual layers of Ta2O5 and graphene over silver-coated unclad core of a silica optical fiber. The performance of sensing probes is studied in terms of the phase difference arising between TM and TE polarized components of the incident light as they propagate through the sensing region, besides their SPR responses towards varying refractive index of analyte layer, making use of the transfer matrix theory for stratified isotropic optical media in conjunction with geometrical optics. Theoretical investigations reveal that the probe having multi-layered arrangement of Ta2O5 and graphene possesses maximum sensitivity of propagating phase difference with magnitude 4.852 × 105 Deg/RIU at analyte refractive index of 1.33 in comparison to probes with individual Ta2O5 (3.731 × 105 Deg/RIU) and graphene (0.362 × 105 Deg/RIU) layers. Moreover, the design parameters of the probes have been numerically maneuvered with an aim of achieving an analyte refractive index of 1.33 in transmitted light spectrum to display the feasibility of proposed sensor in biochemical fields. The reported results unfold an innovative perspective to widen the application horizon of fiber-optic SPR sensors in phase interrogation scheme. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) biosensor is widely used for its high precision and real-time analysis. In this paper, SPR biosensor based on the hybrid structure of metal–indium tin oxide (ITO)–WS2 are proposed and investigated. By optimizing the thickness of metals (Au, Cu, Ag), ITO and WS2, the reflectivity of 2.932 × 10−7 a.u and highest phase sensitivity of 1.711 × 106 deg/RIU are obtained by using Ag–ITO–WS2-dielectric structure. Compared with the traditional metal-based SPR sensor, the performance of the proposed one is improved up to ~ 25.8 times. The results show that ITO and WS2 have an important effect on enhancing SPR sensing performance. [ABSTRACT FROM AUTHOR]

In this paper, a surface plasmon resonance (SPR) sensor based on the hybrid structure of silver (Ag)-indium tin oxide (ITO)-graphene is proposed and investigated. SPR biosensors are subdivided into three kinds of structures Ag, Ag-graphene, and Ag-ITO-graphene, when carried out using their respective optimized structure parameters. According to our analysis and comparison, the ITO-assisted SPR biosensor has an optimal reflectivity of 3.587 × 10−8 and a maximum phase sensitivity of 1.707 × 106°/RIU, which shows that ITO can be employed to further enhance the SPR sensing performance even with the existence of graphene. [ABSTRACT FROM AUTHOR]