Bolstering the optomechanical performances of optically levitated nanoparticles through wavefront shaping

In optical levitation, small particles are trapped in vacuum at the focal spot of a laser. The laser beam produces an optical force equivalent to a mechanical spring and the system is akin to a simple mass-spring resonator displaying kHz oscillations [1]. Because levitated systems outperform other types of mechanical resonators, they are currently exploited to achieve high-sensitivity metrology, detect gravitational waves or search for dark matter. Like any other optomechanical platform, the functionalities and performances of levitated objects are ultimately governed by the interplay between optical and mechanical modes. As a result, there is currently strong incentives in the community to tame and tune optomechanical interactions. Aside from levitation, wavefront-shaping techniques revealed remarkable to govern the propagation of light through multiple-scattering media (e.g., bio-tissues), and therefore display an ability to harness light-matter interactions. Wavefront shaping is typically achieved using a spatial modulator (e.g. a SLM) that shapes the optical phase of an incoming field and adjust its scattering by the environment. Importantly, recent works have shown that these techniques can serve to control the optical forces exerted on one or several particles [2]. In this talk, we will experimentally demonstrate that wavefront shaping can be harnessed to expand the functionalities and the performances of levitated nanoparticles. In particular, we will show that it can bolster the mechanical resonance of the particles or reduce their photonic recoil [3]. We will also introduce how wavefront shaping can serve to manipulate and cool several nanoparticles in parallel [4]. [1] Millen et al., Reports on Progress in Physics, 83(2), 026401. [2] Būtaitė et al., Science Advances 10 (27), [3] Kleine et al., in preparation. [4] Hüpfl and Bachelard et al., Physical Review Letters, 130(8), 083203.