摘要：Vibrating nano and micromechanicalstructures have been the subject of extensiveresearch for the development of ultrasensitivemass sensors for spectrometry, chemicalsensing and biomedical analysis. In short, theminimum detectable mass is proportional tothe effective mass of the resonator andsensitivity improves if mechanical dissipationis reduced. Device miniaturization anddissipation control are therefore crucial. Inliquids, the energy losses are high andtherefore the mass sensitivity is usuallydiminished dramatically. To circumvent thisproblem, novel structures are proposed, likemicro-channels or micro-capillars where theliquid flows directly inside the resonators.While these structures indeed show lowermechanical dissipation, they will hardly beminiaturized. Here we demonstrate thepotential of nano-optomechanical diskresonators during this context, especially thatspecialize in high-frequency radial breathingmodes of those structures. Miniaturesemiconductor mechanical disks, with theirhigh mechanical Q even in air (>103), theirLow Mass (pg) and high mechanicalfrequency (GHz), present clear assets formass sensing applications. However, theyhave not been operated in liquids so far. Here,we experimentally, numerically andanalytically investigate the interaction of suchvibrating disk resonators with arbitraryliquids, and propose models for both thefrequency shift and dissipation of theirmechanical modes. Nano-optomechanicaldisk resonators finally emerge as probes ofrheological information of unprecedentedsensitivity and speed, opening applications inhigh frequency sensing and fundamentalscience.
