Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 71: Poster: Plasmonics and Nanooptics

O 71.1: Poster

Wednesday, March 20, 2024, 18:00–20:00, Poster D

Light-driven Microdrones — •Carsten Büchner, Jin Qin, and Bert Hecht — Nano-Optics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Germany

The precise manoeuvring of microscopically small objects is a major component of today's microrobotics research and promises a wide range of applications in areas such as micromanufacturing or medicine. Most microrobots use magnetic, acoustic or chemical methods to generate the required propulsion. Here, we demonstrate the fabrication and steering of microdrones that are controlled solely by optical forces in unfocussed light fields. The architecture of the microdrones with a lateral size of approximately 2 um and a mass of 2 pg is comparable to recreational drones and can be realised with two or four motors. The nanomotors, which are individually addressable chiral plasmonic nanoantennas, resonantly scatter the circular polarization components of the driving light into well-defined directions, thus achieving thrust exclusively by photon recoil forces. Two overlapping unfocused light fields of 830 and 980 nm wavelength are used to address the motors. This allows the microdrone to operate in 2D in all three degrees of freedom in a fluid environment. With the help of electro-optic modulators, the properties of the light fields can be changed both quickly and precisely, thus varying the movement direction of the drone. By implementing optical tweezers in the drone body, the drones are capable of transporting and releasing nano-sized cargos like nanodiamonds. Biological applications such as the manipulation of red blood cells, yeast cells or bacterias are also conceivable and are being investigated.

Keywords: microrobot; nanooptics; plasmonic nanoantenna