Radiative and Non-radiative Surface Plasmon Resonance: Comparison of Real-Time Sensing Performance
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Radiative and Non-radiative Surface Plasmon Resonance: Comparison of Real-Time Sensing Performance Leiva Casemiro Oliveira 1 & Antonio Marcus Nogueira Lima 2 Received: 26 November 2019 / Accepted: 22 March 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The work presents a surface plasmon resonance sensor able to operate the non-radiative and radiative surface plasmons simultaneously. The optical coupling between photons and surface plasmons was mediated by a rough surface, allowing the photon emission by radiative plasmons excitation process. Experimental tests with reversible and irreversible binding were performed, and the results were compared. The SPR curve profile indicates normalized values < 1 for SP absorption and values > 1 for SP emission. This feature suggests the involvement of localized SP-states that co-exist in the film with delocalized propagating SP state. The data extraction process and the performance of these two excitation forms are also reported. The higher performance of the non-radiative surface plasmons absorption is by a factor of 4. Keywords Thin-film devices . Optical transducers . Surface plasmon resonance spectroscopy . Radiative SPR
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Introduction Surface plasmons (SP) are electromagnetic waves propagating along with an interface between two media with dielectric constants of opposing signals [1]. The surface plasmon resonance (SPR) is usually obtained with the SP optical excitation by prism coupler, which has its surface covered by a thin metal layer. This approach is the so-called Kretschmann configuration [2]. In this configuration, an evanescent field is generated at this metal-substance interface and interacts resonantly with the SP at the prism-metal interface. The SPR phenomenon is
* Leiva Casemiro Oliveira [email protected] Antonio Marcus Nogueira Lima [email protected] 1
Department of Computer Science, Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, RN 59625-900, Brazil
2
Department of Electrical Engineering, Universidade Federal de Campina Grande (UFCG), Campina, PB, Brazil
remarkably sensitive to refractive index changes of the substances and other optical parameters, becoming a powerful technique for biosensing applications [3]. The existence of radiative and non-radiative SPR by attenuated total reflection (ATR) in the Kretschmann configuration is described in the literature [4–8]. For the non-radiative SPR, the energy and momentum of the optical coupling between photons and plasmons wave vectors are conserved. This is obtained by depositing a thin metallic layer on polished surfaces and illuminating it with a fixed angle (angular interrogation mode (AIM)) or a fixed wavelength (spectral/wavelength interrogation mode (WIM)) [9]. In the presence of unpolished/rough surfaces, under certain conditions, photons can be emitted from the SP propagation, and the roughness allows the conservation of the wave vectors by means of momentum transfer at the resonance point. This situation describes the radia
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