Spatial resolution and refractive index contrast of resonant photonic crystal surfaces for biosensing
| Autor: | Triggs, G. J., Fischer, M., Stellinga, D., Scullion, M. G., Evans, G. J O, Krauss, T. F. |
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| Přispěvatelé: | EPSRC, University of St Andrews. School of Physics and Astronomy |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
lcsh:Applied optics. Photonics
polarization Spatial resolution refractive index contrast NDAS Physics::Optics lcsh:TA1501-1820 biosensor Article Resonant surface grating QC Physics Refractive index contrast Polarization lcsh:QC350-467 Grating Photonic crystal spatial resolution photonic crystal lcsh:Optics. Light Biosensor QC |
| Zdroj: | IEEE Photonics Journal, Vol 7, Iss 3, Pp 1-10 (2015) IEEE photonics journal |
| ISSN: | 1943-0655 |
| Popis: | This work was supported in part by the EPSRC of U.K. under Grant EP/J01771X/1 (Structured Light), by the BBSRC under Grant BB/L0181160/1 [Label-free, Real-time, Spatial resolution (LRS) immunoassay], and by the Wellcome Trust under Grant 097829/Z/11/A. By depositing a resolution test pattern on top of a Si3N4 photonic crystal resonant surface, we have measured the dependence of spatial resolution on refractive index contrast Δn. Our experimental results and finite-difference time-domain (FDTD) simulations at different refractive index contrasts show that the spatial resolution of our device reduces with reduced contrast, which is an important consideration in biosensing, where the contrast may be of order 10-2. We also compare 1-D and 2-D gratings, taking into account different incidence polarizations, leading to a better understanding of the excitation and propagation of the resonant modes in these structures, as well as how this contributes to the spatial resolution. At Δn = 0.077, we observe resolutions of 2 and 6 μm parallel to and perpendicular to the grooves of a 1-D grating, respectively, and show that for polarized illumination of a 2-D grating, resolution remains asymmetrical. Illumination of a 2-D grating at 45 degrees results in symmetric resolution. At very low index contrast, the resolution worsens dramatically, particularly for Δn |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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