Hybrid Plasmonic Directional Coupler-Based Refractive Index Biosensor.
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| Title: | Hybrid Plasmonic Directional Coupler-Based Refractive Index Biosensor. |
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| Authors: | Sharma, Vinod K.1 (AUTHOR) vksharma@keshav.du.ac.in |
| Source: | Plasmonics. Oct2025, Vol. 20 Issue 10, p9029-9041. 13p. |
| Subjects: | Biosensors, Spectral sensitivity, Detectors, Plasmonics, Surface plasmon resonance, Directional couplers, Opacity (Optics) |
| Abstract: | We propose a prism-based multilayer plasmonic waveguide sensor structure which supports ultra-long-range plasmonic modes at optical wavelengths. We show that a dielectric waveguide placed parallel to the plasmonic guide and separated by a low index dielectric layer can significantly increase the propagation length of the plasmonic modes. The sensor structure forms a hybrid plasmonic directional coupler. The extended range of 0.13 cm can be achieved for the hybrid long-range plasmonic mode supported by the structure. The full width at half minima is very small which makes this configuration very efficient for sensing applications. Both angular and spectral modes of sensing are investigated with Ag and Au as plasmonic waveguides. We also show that the spectral sensitivity increases with decrease in the metal layer thickness (with optimized buffer thickness) and spectral sensitivity of 29480 nm/RIU with very high figure of merit could be achieved at wavelength 0.6328 μm for aqueous medium (which is desirable for bio-sensing applications). The figure of merit for angular mode is also very high. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | We propose a prism-based multilayer plasmonic waveguide sensor structure which supports ultra-long-range plasmonic modes at optical wavelengths. We show that a dielectric waveguide placed parallel to the plasmonic guide and separated by a low index dielectric layer can significantly increase the propagation length of the plasmonic modes. The sensor structure forms a hybrid plasmonic directional coupler. The extended range of 0.13 cm can be achieved for the hybrid long-range plasmonic mode supported by the structure. The full width at half minima is very small which makes this configuration very efficient for sensing applications. Both angular and spectral modes of sensing are investigated with Ag and Au as plasmonic waveguides. We also show that the spectral sensitivity increases with decrease in the metal layer thickness (with optimized buffer thickness) and spectral sensitivity of 29480 nm/RIU with very high figure of merit could be achieved at wavelength 0.6328 μm for aqueous medium (which is desirable for bio-sensing applications). The figure of merit for angular mode is also very high. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 15571955 |
| DOI: | 10.1007/s11468-025-02971-z |
