Automated manipulation of micro-and nanosized objects using robotic setups constitutes a major challenge due to the force-scaling laws and the limited control possibilities on that scale. This paper presents a new developed approach for automated manipulation of individual colloidal particles using a dedicated dualprobe setup inside a scanning electron microscope. Based on tailored probe geometries, the setup allows for reliable pick-up and release sequences of individual particles. Applying image processing of the visual feedback provided by the microscope enables for direct and fast control of the complex manipulation routines and thus allows for fully automated alignment sequences. Experimental results reveal a high repeatability of the process with hitherto unrivaled precision. The advantages and limits of this technique are highlighted with respect to further application scenarios.
We demonstrate the capability of single plasmonically active nanoslits for sensing of small fine dust particles via surface-enhanced infrared absorption (SEIRA) spectroscopy. Investigating phononic excitations of individual spherical silica particles coupled to the plasmonic excitation of single nanoslits, we are able to detect and chemically identify single spheres with diameters of 240 nm by their enhanced phononic signal. The single silica spheres in nanoslits lead to Fano-type phononic signals on the plasmonic background. The enhancement of the phononic silica signal is highest for particles located in the middle of the slit, in accordance with the FDTDsimulated near-field distribution along the slit at resonance. Our results reveal, that resonant plasmonic nanoslits are promising substrates for SEIRA spectroscopy of fine and ultra fine dust particles and guide the way toward SEIRA based dust sensing devices.
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