Using Diffraction to Detect Deflection of the Cantilevers in an Array

We present an optical technique to detect cantilever deflection of an array using Fraunhofer diffraction patterns. Application areas include probe-based data storage. Intensity profiles of different cantilever arrays are captured on a CCD camera and compared with our model. These measurements are in excellent agreement with the Fraunhofer theory, less than 3% deviation is found. Each cantilever can either be deflected by a fixed amount or undeflected. Based on noise measurements on our setup and intensity patterns simulations, we predict that this method allows the measurement of 1nm deflections in an array of six cantilevers with an SNR of 35dB.