  Integrated chemical and biological sensors give advantages in cost, size and
weight reduction and open new prospects for parallel monitoring and analysis.
Biosensors based on nanoelectromechanical systems (NEMS) are the most
attractive candidates for the integrated platform. However, actuation and
transduction techniques (e.g. electrostatic, magnetomotive, thermal or
piezoelectric) limit their operation to laboratory conditions. All-optical
approach gives the possibility to overcome this problem, nevertheless, the
existing schemes are either fundamentally macroscopic or excessively
complicated and expensive in mass production. Here we propose a novel scheme of
extremely compact NEMS biosensor monolithically integrated on a chip with
all-nanophotonic transduction and actuation. It consists of the photonic
waveguide and the nanobeam cantilever placed above the waveguide, both
fabricated in the same CMOS-compatible process. Being in the near field of the
strongly confined photonic mode, cantilever is efficiently actuated and its
response is directly read out using the same optical waveguide, which results
in a very high sensitivity and capability of single-molecule detection even in
atmosphere.
