Nanoscale plasmonic phase sensor
Using the localized surface plasmon resonance (LSPR) of gold nanoparticles for sensing applications has attracted considerable interest, since it can be very sensitive, even down to a single molecule, and selective for a specific analyte molecule with a suitable surface modification. LSPR sensing is usually based on the wavelength shift of the LSPR or a Fano resonance. Here, we present a new experimental approach based on the phase of the light scattered by a single gold nanoparticle by equipping a confocal microscope with an additional interferometer arm similar to a Michelson interferometer. The detected phase depends on the shape of the nanoparticle and the refractive index of the surrounding medium and can even be detected for off-resonant excitation. This can be used as a new and sensitive detection method in LSPR sensing, allowing the detection of changes to the local refractive index or the binding of molecules to the nanoparticle surface.
KeywordsSingle particle sensing Gold nanotriangle Particle plasmon Elastic scattering Optical microscopy Phase
This study received funding from DFG grants ME 1600/13-3, BR 532/1-1 and FL670/7-1.
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Conflict of interest
The authors declare that they have no conflict of interest.
- 27.Hepel M, Stobiecka M. Detection of oxidative stress biomarkers using functional gold nanoparticles. Fine particles in medicine and pharmacy: Springer; 2012. p. 241–281.Google Scholar
- 30.van de Hulst HC. Light scattering by small particles: Courier Corporation; 1981.Google Scholar