Trapping with light has given us unprecedented control over to the micro-world for several decades now. Optical traps can take different forms, the most ubiquitous one being a tightly focused Gaussian beam, which has proved itself to be extremely versatile. However, when it comes to trapping particles larger than the illumination wavelength, the diffraction limited “footprint” of a Gaussian trap is small in comparison, inefficiently achieving momentum transfer from light to particle, thus resulting in a lower trapping stiffness. In this work we investigate how the structure of the trapping light can be custom-tailored to best suit a specific particle (and indeed its environment and the optical system). We demonstrate both numerical and live-feedback based optimisations aimed at sculpting light into shapes that substantially enhance optical trapping stiffness of micro-spheres in three dimensions simultaneously, when compared to a conventional Gaussian trap [1].

[1] Unė G. Būtaitė, Christina Sharp, Michael Horodynski, Graham M. Gibson, Miles J. Padgett, Stefan Rotter, Jonathan M. Taylor, and David B. Phillips. "Photon-efficient optical tweezers via wavefront shaping." arXiv preprint arXiv:2304.12848 (2023).