SAMOP 2021 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 3: Photonics and Laser Development
Q 3.3: Poster
Montag, 20. September 2021, 16:30–18:30, P
Characterising and tracking the three-dimensional motion and rotation of individual nanoparticles using a high-finesse fibre-based microcavity — Larissa Kohler1, •Shalom Palkhivala1, Matthias Mader2, Christian Kern1, Martin Wegener1, and David Hunger1 — 1Karlsruher Institut für Technologie, Karlsruhe, Germany — 2Ludwigs-Maximilians-Universität, Munich, Germany
While many current techniques for nanoparticle sensing are based on labelling, we present a fibre-based high-finesse Fabry-Perot microcavity capable of sensing unlabelled nanoparticles. The optical microcavity is integrated with microfluidic channels for the detection of nanoparticles in solution. Silica nanospheres with radii of 25 nm have thus been detected, and their mean refractive index deduced.
Furthermore, the three-dimensional Brownian motion of a single nanoparticle in the cavity is tracked by the simultaneous measurement of the fundamental and two higher-order transverse modes. The particle's position can be derived with spatial and temporal resolutions of 8 nm and 0.3 ms respectively. In addition, the rotation of nanoparticles is measured by the polarisation splitting of the fundamental mode. The rotation of nanospheres with a specified roundness of 0.98 can already be investigated with this method.
Work is being done to increase the detection bandwidth and sensitivity, to eventually allow characterisation of the optical and dynamic behaviour of single biomolecules.