In this work, we demonstrate that by bringing together optical and mechanical resonances in single sensing platforms, their performances are significantly enhanced. In particular, we use nano-optomechanical disks, which simultaneously support high quality optical and mechanical modes. First, we apply the simultaneous or dual optical and mechanical sensing technique for monitoring environmental changes. Then, we employ it for detecting individual bacteria, accessing to its optical and mechanical properties. A variety of optical and mechanical resonators have been successfully employed in a diversity of sensing applications. Typically, optical resonators stand out for being extraordinary sensitive, while mechanical resonators are highly reliable. In this sense, optomechanical devices are unique platforms, since they support, at the same time, high quality optical and mechanical modes. Here we highlight the advantages of combining optical and mechanical resonances in a unique sensing platform, improving the sensor assets, together with its reliability and robustness. In particular, we apply nano-optomechanical disks fabricated out of gallium arsenide (Figure 1), which have already shown excellent capabilities when operating in liquids and for biosensing applications [1, 2]. We first apply them for monitoring environmental changes. Notably, the dual sensing approach allows decoupling relative humidity and temperature changes, reaching extraordinary precision, 0.01 % and 100 µK respectively (Figure 2). To further prove the capabilities of this novel method, we employ it for detecting individual bacteria (Figure 3). The technique allows to simultaneously access the bacterium optical and mechanical properties, such as its refractive index, absorption coefficient, mass, rigidity and viscosity [3].

Work produced with the support of a 2021 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. The Foundation takes no responsibility for the opinions, statements and contents of this project, which are entirely the responsibility of its authors. This research is also funded by the Spanish Ministry of Science under the project MicroBIOMS, reference PID2019-109765RA-I00. E.G.S. acknowledges financial support by the Spanish Science and Innovation Ministry through the Ramón y Cajal grant RYC2019-026626-I.

Resumen del trabajo presentado en la 12th International Conference on Metamaterials, Photonic Crystals and Plasmonics - META, celebrada en Torremolinos (España), del 19 al 22 de julio de 2022