Integrated optical readout for miniaturization of cantilever-based sensor system

The authors present the fabrication and characterization of an integrated optical readout scheme based on single-mode waveguides for cantilever-based sensors. The cantilever bending is read out by monitoring changes in the optical intensity of light transmitted through the cantilever that also acts as a waveguide. The complete system is fabricated in the photosensitive polymer SU-8. They show theoretical calculations on the expected sensitivity both when operated in air and liquid and compare these with experimental characterization of the system in air where the cantilever is deflected mechanically. The experimental results compare well with the results obtained from the theoretical calculations. (C) 2007 American Institute of Physics.