The gist of it: this technique could be used to build structures on a micro-scale with high precision, potentially leading to advances in nanotechnology, microfabrication, or the development of new materials with unique properties. Light and breezy reading for futurists and anyone who wants a break from reading about research into new phosphorescent materials.
Photon-efficient optical tweezers via wavefront shaping[1} is a groundbreaking study by Unė Būtaitė and Christina Sharp that focuses on enhancing the strength of 3D optical traps. Optical tweezers are widely used to non-invasively trap and manipulate micro-scale objects using light. Despite their widespread use, the limit of how tightly micro-particles can be trapped in 3D space is not known. Reaching this limit would enable maximally stiff particle trapping for precision measurements on the nanoscale and photon-efficient tweezing of light-sensitive objects.
In this study, the authors develop a theoretical approach using a multi-parameter optimization routine to design custom optical traps for a wide range of micro-particles. They customize the trapping light field to suit a specific particle, aiming to optimize trap stiffness in all three dimensions simultaneously. The researchers show that the confinement volume of micro-spheres held in these sculpted traps can be reduced by one-to-two orders-of-magnitude compared to a conventional optical tweezer of the same power.
The authors then conduct proof-of-principle experiments using a wavefront shaping inspired strategy to suppress Brownian fluctuations of optically trapped micro-spheres in every direction concurrently. This results in order-of-magnitude reductions in their confinement volumes.
The findings of this study pave the way towards the fundamental limits of optical control over the mesoscopic realm. By customizing light fields in concert with specifically engineered micro-particles, it is possible to develop ultra-stiff and high-force optical traps with specialized capabilities. This enhancement in optical trapping will be especially beneficial in applications that require ultra-precise manipulation of micro-particles or those that involve samples intolerant of high optical intensities. Some examples include optical traps for isolating particles as they are cooled to the quantum ground state, precision positioning of microscopic sensors, automated optical assembly of micro-scale structures, and the study of photosensitive biological systems.
Reference
- Būtaitė, U. G., Sharp, C., Horodynski, M., Gibson, G. M., Padgett, M. J., Rotter, S., Taylor, J. M., & Phillips, D. B. (2023). Photon-efficient optical tweezers via wavefront shaping (arXiv:2304.12848). arXiv. https://doi.org/10.48550/arXiv.2304.12848
