Sensitivity analysis for improving nanomechanical photonic transducers biosensors
D. Fariña, M. Álvarez, S. Márquez, C. Domínguez and L. M. Lechuga.
Journal of Physics D: Applied Physics, 48, 2015, 335401 - DOI: 10.1088/0022-3727/48/33/335401
Abstract: The achievement of high sensitive and highly integrated transducers is one of the main challenges in the development of high-throughput biosensors. The aim of this study is to improve the final sensitivity of an opto-mechanical device to be applied as a reliable biosensor. We report an analysis of the mechanical and optical properties of optical waveguide microcantilevers transducers, and its dependency with the device design and dimensions. The selected layout (geometry) based in two butt-coupled misaligned waveguides display better sensitivities than an aligned one. With this configuration, we find that an optimal microcantilever thickness range between 150 nm and 400 nm, would increase both the microcantilever bending during the biorecognition process and the optical sensitivity up to 4.8 10-2 nm-1, an order of magnitude higher than other similar opto-mechanicals devices. Moreover, the analysis shows that single mode behaviour of the propagating radiation is required to avoid the modal interference that could misunderstand the readout signal.