Bragg-Scattered Surface Plasmon Microscopy: Theoretical Study
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We present a new approach to surface plasmon microscopy with high refractive index sensitivity and spatial resolution that is not limited by the propagation length of surface plasmons. It is based on a nanostructured metallic sensor surface supporting Bragg-scattered surface plasmons. We show that these non-propagating surface plasmon modes are excellently suited for spatially resolved observations of refractive index variations on the sensor surface owing to their highly confined field profile perpendicular to as well as parallel to the metal interface. The presented theoretical study reveals that this approach enables reaching similar refractive index sensitivity as regular surface plasmon resonance (SPR) microscopy and offers the advantage of improved spatial resolution when observing dielectric features with lateral size <10 μm for the wavelength around 800 nm and gold as the SPR-active metal. This paper demonstrates the potential of Bragg-scattered surface plasmon microscopy for high-throughput SPR biosensing with high-density microarrays.
KeywordsSurface plasmon resonance SPR microscopy SPR imaging Diffraction grating Biosensor
The authors would like to acknowledge the help of Dr. Roman Bruck in implementing DiPoG software on a Linux-based computation cluster. Support for this work was provided in part by the Center of Innovation and Technology of Vienna (ZIT) and the Austrian NANO Initiative (FFG and BMVIT) through the NILPlasmonics project within the NILAustria cluster (www.NILAustria.at).
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