Acoustoplasmonic metasurface design for acoustic wavefront shaping and polarization-tunability

Plasmonic metasurfaces describe a class of optical metasurfaces composed of resonant plasmonic nanoparticles, which exhibit strong concentration, scattering, and absorption of electromagnetic energy at subwavelength scales. While their absorptive properties can be a hindrance in all-optical applications, they are advantageous for electromagnetic-to-mechanical energy conversion. This phenomenon is leveraged in acoustoplasmonic metasurfaces, in which incident light excites an acoustic wave. We analytically and numerically examine this acoustic wavefront actuation, which involves the coupling of optical, thermoelastic, and acoustic mechanisms for gold nanospheres. We furthermore demonstrate how nanoparticle anisotropy and relative nanoparticle arrangement enables polarization-tunable acoustic wavefront shaping. The foundational understanding of these mechanisms enables rationally designed wavefront shaping via optimization algorithms. We finally turn our attention towards the experimental realization of these analytical and numerical studies, namely tunable acoustic wavefront actuation using polarized light.