# Characterization and tracking of the three-dimensional translational motion and rotation of single nanoparticles using a fiber-based microcavity with high finesse

Kohler, Larissa Anne-Marie

## Abstract (englisch):

Sophisticated new sensor techniques have to be developed to enable the detection of the temporal dynamics of single nanoparticles and molecules. Some of the new microscopy techniques are based on nanoparticle labeling, achieving high sensitivity on the single nanometer scale, but also changing the nanoparticle's natural behavior. In this work, a fiber-based Fabry-Pérot (FP) microcavity with high finesse is presented, which allows the detection of unlabeled nanoparticles. Single nanoparticle resolution is achieved by forcing the light to thousands of round trips between two high-reflective mirrors of micrometer size and consequently enhancing the interaction between light and nanoparticle.
So far, fiber-based FP cavities in air, vacuum and liquid helium have been reported in the past. In order to enable single nanoparticle measurements in liquids, two different microfluidic channels are demonstrated. Both channels allow an easy integration of the fiber-based FP cavity, provide a controllable laminar flow, and the measurement of small sample volumes.
Furthermore the microfluidic channel and the integrated FP cavity are embedded in a sensing platform, that provides a high passive stability of $\sim1$pm and a low root-mean-square measurement noise of $0.39$pm. ... mehr

 Zugehörige Institution(en) am KIT Karlsruhe School of Optics & Photonics (KSOP)Physikalisches Institut (PHI) Publikationstyp Hochschulschrift Publikationsdatum 07.10.2021 Sprache Englisch Identifikator KITopen-ID: 1000138731 Verlag Karlsruher Institut für Technologie (KIT) Umfang 179 S. Art der Arbeit Dissertation Fakultät Fakultät für Physik (PHYSIK) Institut Physikalisches Institut (PHI) Prüfungsdatum 16.07.2021 Schlagwörter three-dimensional tracking, single nanoparticle detection, fiber-based Fabry-Pérot interferometer, optical polarizability, microfluidic channel, hydrate shell, rotational Brownian motion, translational Brownian motion, diffusivity, hydrodynamic radius, optical sensor, Monte Carlo simulation, autocorrelation Referent/Betreuer Hunger, D.
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