Plasmonic metamaterial absorber for broadband manipulation of mechanical resonances

Metamaterials(1-5) are artificial materials that exhibit unusual properties for electromagnetic and sound waves. The quanta, namely photons and phonons, of these waves interact resonantly with these exotic man-made materials enabling many applications(1). For instance, resonant light absorption(6-8) in photonic metamaterials can efficiently convert optical energy into heat based on the photothermal(9) effect. Here, we present a plasmonic metamaterial that simultaneously supports thermomechanically coupled optical and mechanical resonances for controlling mechanical damping with light(10). In this metamaterial absorber(6) with voltage-tunable Fano resonances, we experimentally achieve optically pumped coherent mechanical oscillations(10) based on a plasmomechanical(11-19) parametric gain mechanism over an similar to 4 THz bandwidth. Through the reverse effect, optical damping of mechanical resonance is also achieved. Our results provide a metamaterial-based approach for optical manipulation of the dynamics of mechanical oscillators.