Light-driven microdrones

• Applicants: Professor Dr. Bert Hecht; Dr. Xiaofei Wu
• Subject Area: Experimental Condensed Matter Physics ; Microsystems ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 438123468

We propose micrometer-sized robotic devices that can be maneuvered in all six degrees of freedom of 3D motions by making use of optical nanomotors. The optical nanomotors are designed to exhibit resonant directional scattering of unfocused incident photons of certain wavelengths and circular polarizations. Using a properly arranged set of such nanomotors embedded in a microscopic transparent body, it will be possible to implement independent control of all degrees of freedom of the latter, i.e., forward-backward, left-right, up-down, yaw, pitch, and roll. Such complete control will enable us to implement a fast feedback control to counter-act Brownian motion and thus stabilize the position and orientation of the object with high precision, paralleling the functionality of macroscopic multirotor drones. These devices are therefore called "light-driven microdrones". During the initial funding period, we successfully developed microdrones capable of maneuvering in three axes of 2D motion-translational movements in the forward-backward and left-right directions, and rotational yaw published in Nature Nanotechnology. Additionally, we established a proof of principle for a 2D feedback control to stabilize position and orientation against Brownian motion. The design involves microdrones equipped with four nanomotors, which are controlled by modulating the power and polarization of two unfocused laser beams of distinct wavelengths. In this follow-up proposal, we aim to complete the development of light-driven microdrones, achieving comprehensive 3D maneuverability combined with advanced feedback control for nanometer-scale precise motion. Additionally, we will implement microfluidic chips to enhance the experimental capabilities and enable applications of microdrones while improving sustainability. Leveraging this fully developed microdrone system, we will conduct a pivotal application experiment which involves employing a microdrone equipped with a resonant gold nanotip to precisely scan the membrane of a living cell within a liquid medium. The objective is to measure the tip-enhanced Raman scattering spectra of membrane proteins, showcasing the significant potential of microdrones as a robust platform for performing high-precision sensing and manipulation tasks, opening new avenues for innovative experimental research.

• DFG Programme: Research Grants