Shaping Optical Forces: From Laser-Driven Lightsails to Optomechanical Nonlinear Dynamics

Optical forces have driven transformative breakthroughs in science, including optical tweezers, atom cooling, and Bose-Einstein condensation, each recognized with a Nobel Prize in Physics. Recent years have seen great progress in nanophotonics, allowing us to manipulate light at the nanoscale by designing materials with complex geometries of sub-wavelength structures. The merging of optical forces and nanophotonics has led to the emerging field of optomechanical control of nanostructured objects. This new paradigm enables great flexibility in designing optical forces, allowing to manipulate large objects over long distances and thus unlocking exciting opportunities in both fundamental science and technological innovation.

In this talk, I will present my research in this area, introducing novel methods for shaping and characterizing optical forces, and studying the resulting optomechanical nonlinear dynamics. I will first introduce our platform for simultaneously measuring optical forces and powers, utilizing the coupled thermal, mechanical, and optical dynamics induced by the driving laser beam. Using this platform, we characterized the forces acting on a thin membrane, which is relevant to applications such as laser-driven lightsails for space exploration. Next, I will demonstrate how nanopatterning can be used to design systems capable of pulling objects over large distances using optical forces. Finally, I will discuss the intriguing nonlinear dynamics observed in our membranes. Within the bistable regime induced by Duffing nonlinearity, stochastic thermal fluctuations allow us to control the intermodal energy exchange rate, leading to significant optomechanical nonlinearities.