Integrated optical read-out for miniaturisation of cantilever-based sensor system

Abstract

We present the fabrication and characterisation of an integrated optical read-out 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 photo-sensitive polymer SU-8. We show theoretical calculations on the expected sensitivity both when operated in air and liquid and compare these with experimental characterisation of the system in air where the cantilever is deflected mechanically. The experimental results compare well with the results obtained from the theoretical calculations.