Regensburg 2022 – scientific programme
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BP: Fachverband Biologische Physik
BP 12: Poster 2
BP 12.67: Poster
Tuesday, September 6, 2022, 17:30–19:30, P4
Investigating Nanoparticle Dynamics in a High-Finesse Optical Microcavity — Larissa Kohler, •Shalom Palkhivala, and David Hunger — Karlsruhe Institute of Technology – Institute of Physics, Karlsruhe, Germany
We explore the dynamics of nanoparticles using a novel fibre-based high-finesse Fabry-Perot microcavity with integrated microfluidic channels. Silica nanospheres with radii down to 25 nm and gold nanorods with lengths of 20 nm have thus been investigated.
The three-dimensional Brownian motion of a single nanosphere in the cavity has been tracked by the simultaneous measurement of the fundamental and higher-order transverse modes. The particle’s position was derived with spatial and temporal resolutions of down to 8 nm and 0.3 ms respectively.
To resolve the faster motion of even smaller nanoparticles, a cavity-locking system has been implemented. This achieved an rms stability of 4% of the resonance linewidth in a water-filled cavity having a finesse of 5 × 104. Hence, the dynamics of 20 nm gold nanorods could be detected with high measurement bandwidth. We shall report progress towards a quantitative evaluation of nanorod diffusion, and the measurement of nanoparticle rotation using a cavity-locked polarisation-splitting scheme.
Based on this, we aim to explore the dynamic and optical behaviour of single biomolecules, such as DNA.