An Astigmatic Detection System for Polymeric Cantilever-Based Sensors

Abstract EN

We demonstrate the use of an astigmatic detection system (ADS) for resonance frequency identification of polymer microcantilever sensors.

The ADS technology is based on a DVD optical head combined with an optical microscope (OM).

The optical head has a signal bandwidth of 80 MHz, allowing thermal fluctuation measurements on cantilever beams with a subnanometer resolution.

Furthermore, an external excitation can intensify the resonance amplitude, enhancing the signal- to-noise ratio.

The full width at half maximum (FWHM) of the laser spot is 568 nm, which facilitates read-out on potentially submicrometer-sized cantilevers.

The resonant frequency of SU-8 microcantilevers is measured by both thermal fluctuation and excited vibration measurement modes of the ADS.