Optical super-torque induced by Mie-resonant modes

Abstract: We introduce the concept of resonant optical torque that allows enhancing substantially a transfer of optical angular momentum (AM) of light to a subwavelength particle. We consider high-index cylindrical dielectric nanoparticles supporting Mie resonances, and explore a transfer of AM and how it is affected by absorption and particle shape. We analyse a simple trapping geometry of standing wave patterns created by opposite helical light waves. We uncover stable rotation of particles in both nodes and anti-nodes, and also study how specific particle properties influence the resonant optical torque. We demonstrate that adjusting particle losses can maximize spinning torque, and we predict "super-torque" originating from the superabsorption effect at resonances. Our study offers a deeper understanding of the physics of resonant optical torque and its importance in manipulating AM transfer in optical systems, with promising implications for various fields and inspiring further research in resonant light-matter interactions.