DETECTION OF DISPLACEMENTS IN THE NANOMETER RANGE BY OPTICAL TUNNELING

Our concern is the exploitation of the so-called optical tunnelling ef fect to detect the cantilever deflection in atomic force microscopy (A FM) caused by the interatomic forces established between a sample surf ace and the force sensor. Towards this end, we have developed a displa cement sensor based on the phenomenon of evanescent wave coupling or t he optical tunnelling effect. Furthermore, we have implemented a compu ter programme simulating a planar model of a three media system (optic al tip, gap and waveguide where total internal reflection occurs). The proposed method is particularly suitable for biophysical applications of AFM.