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Ultra-wide dynamic range fiber-optic SPR sensor based on phase interrogation
Published in Khaled Habib, Elfed Lewis, Frontier Research and Innovation in Optoelectronics Technology and Industry, 2018
Z.L. Song, Y.B. Guo, T.G. Sun, M.T. Liu, Y. Zheng
Surface plasmon resonance (SPR) is a collective free electron oscillation which occurs at a metal-dielectric interface when the wave-vector horizontal component of the incident light matches the propagation constant of the surface plasmon wave (Deng et al. 2017, Huang et al. 2012a). In 1997, Salamon et al. reported a SPR sensor based on coupled plasmon waveguide resonance (CPWR) (Salamon et al. 1997). The sensor incorporates a waveguide layer beneath the surface of the conventional SPR sensor in their design, as shown in Figure 1(b). Different from the conventional SPR sensors, the interference of the waveguide layer in the CPWR device causes sharp dips in both the transverse magnetic (TM, p-wave component) and transverse electric (TE, s-wave component) modes (Grotewohl et al. 2016, Chien & Chen 2004).
Sensor Systems for Label-Free Detection of Biomolecular Interactions: Quartz Crystal Microbalance (QCM) and Surface Plasmon Resonance (SPR)
Published in Yallup Kevin, Basiricò Laura, Iniewski Kris, Sensors for Diagnostics and Monitoring, 2018
Şükran Şeker, M. Taner Vurat, Arin Doğan, A. Eser Elçin, Y. Murat Elçin
SPR systems consist of several main components: a light source, a metallic layer (gold, silver, etc.), a flow channel, a polarizer, a chopper, a prism, a glass slide, a light detector, a photodiode, and a lock-in amplifier (Figure 8.6). The incident beam is polarized in a parallel orientation to the plane of incidence, known as p-polarization. The chopper modulates the intensity of the incident light, and the lock-in amplifier is used to measure the light with reference to the chopping frequency; used together they improve the signal-to-noise ratio. The lens focuses a laser beam on the prism base surface, which is subsequently measured with an ultrasensitive photodiode. The Kretschmann configuration involves a thin metal film in direct contact with the prism base for the excitation of the surface plasmon (Figure 8.6) [68].
Immune Systems, Molecular Diagnostics, and Bionanotechnology
Published in Anil Kumar Anal, Bionanotechnology, 2018
SPR is a physical optical phenomenon based on the change in the refractive index on the metal surface. A plane-polarized light beam entering the higher refractive index medium (glass prism) can undergo total internal refraction above a critical angle of incidence. Under these conditions, an electromagnetic field light component, that is, evanescent wave will penetrate into the gold film. At a specific angle of incidence, interaction of this wave with free oscillating electrons at the gold film surface will cause the excitation of surface plasmon’s resulting subsequently in a decrease in the reflected light intensity. This phenomenon is called SPR and occurs only at a specific angle of incident light. SPR system thus detects changes in the refractive index of the surface layer of a solution in contact with the sensor chip (Hodnik and Anderluh 2009).
Gold nanoparticles (AuNPs) and graphene oxide heterostructures with gold film coupling for an enhanced sensitivity surface plasmon resonance (SPR) fiber sensor
Published in Instrumentation Science & Technology, 2022
Since 1993 when the optical fiber surface plasmon resonance (SPR) sensing was first proposed by Jorgenson et al.,[1] it has been widely used in life sciences, environmental monitoring, medical testing and other fields on account of its unique advantages of high sensitivity, diminutive size, and easy integration.[2–5] SPR is an electromagnetic resonance coupling between light waves and plasma waves on the surface of a metal film, where the electric field energy is localized between the metal film surface and the ambient medium, and is sensitive to the latter’s refractive index.[6] However, its sensitivity and repeatability create problems for the determination of low concentrations and small molecules.[7,8]
Investigation of a high-sensitivity surface plasmon resonance sensor based on the eccentric core quasi D-shape photonic quasi-crystal fiber
Published in Journal of Modern Optics, 2021
Yudan Sun, Haiwei Mu, Jiudi Sun, Qiang Liu, Chao Liu, Wei Liu, Jin Zhao, Jingwei Lv, Tao Sun, Paul K. Chu
Surface plasmon resonance (SPR) sensors have attracted widespread attention due to excellent characteristics such as label-free, high-sensitivity, and real-time monitoring and been applied to food safety, gas detection, liquid detection, biosensing, and poisonous materials detection [1–4]. SPR is an optical phenomenon caused by collective oscillations of free electrons at the interface between the metal and dielectric materials [5]. While the common plasmonic metals are gold (Au), silver (Ag), and copper (Cu) [6,7], alternative metal compounds and metal oxides with stable plasmonic properties and lower price such as indium nitride (InN), indium tin oxide (ITO), zinc oxide (ZnO), and tantalum oxide (Ta2O5) are attracting increasing interest [8–11]. SPR is extremely sensitive to changes of the refractive index (RI) of the external medium and so the phenomenon can be exploited by RI sensors. Traditional SPR-based RI sensors are based on prism excitation, but the bulky structure and complicated operation have heretofore limited wider application especially portable and remote sensing [12]. In this respect, the microstructure optical fiber (MOF) has been proposed to replace the prism-type structure on account of advantages such as miniaturization, low cost and high-sensitivity [13].
High quality factor D-type fiber surface plasmon resonance (SPR) sensor based on the modification of gold nanoshells
Published in Instrumentation Science & Technology, 2020
Li-Ye Niu, Qi Wang, Wan-Ming Zhao, Jian-Ying Jing
Surface plasmon wave can produce SPR effect under certain conditions. When SPR occurs, the intensity of reflected or scattered light emitted from the surface of metal material greatly decreases, while LSPR occurs at the absorption peak of the metal nanostructure.[12] The SPR and LSPR characteristics of metal materials are closely related to the refractive index of metal surface medium. When the refractive index of environmental medium on the surface of metal material changes, the position of SPR resonance peak changes accordingly. The SPR effect of metal materials may be used to detect the surface refractive index, and then reflect the environmental changes near the surface.[13] The concentration level of analyte to be measured may be determined according to the position change of SPR resonance peak. When the refractive index of the environment around the sensor changes, the change is Δn, which causes the resonance wavelength shift of the sensor, and the change is ΔL. The sensitivity of the sensor can be evaluated using Equation (1).[6]