Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.


Sensitivity of Interferometric Cross-Polarization Microscopy for Nanoparticle Detection in the Near-Infrared

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Benjamin T. Miles, Elizabeth C. Robinson, Erik M. H. P. van Dijk, Ian D. Lindsay, Niek F. van Hulst, and Henkjan Gersen
ACS Photonics
online nov. 3, 2015

We address the sensitivity of Interferometric Cross-Polarization Microscopy by comparing scattering and absorption by spherical 10 nm nanoparticles through a combination of modeling and experiment. We show that orthogonality of light in the two polarization branches of Cross-Polarization Microscopy ensures that only light that has interacted with a nanoparticle is interferometrically enhanced. As a result background-free shot noise-limited detection is achieved for sub-μW optical powers at the sample. Our modeling in particular shows that in the near-infrared regime, above the plasmon resonance frequency of spherical nanoparticles, the cross-polarization approach is several orders of magnitude more sensitive than conventional extinction based detection. This enhanced near-infrared sensitivity for spherical nanoparticles is promising for applications requiring low absorption and low power imaging of nanoparticles in cells.

Keywords: confocal microscopy; nanoparticle detection; Mie scattering; cross-polarization imaging; gold nanoparticles; background free detection; detection sensitivity
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