A Cantilever Force Sensor Combined With a Spherical Reflecting Mirror for Sensitivity Enhancement of an Optical Detection System

By fabricating a microspherical reflecting mirror (MSRM) on the tip of a cantilever, the deflection angle of the laser beam is significantly magnified. Therefore, the sensitivity of an optical sensing system is enhanced. The curvature of the spherical reflecting mirror determines the system sensitivity. Given a certain bending amount and a fixed distance between the cantilever and the position-sensing detector, the cantilever combined with an MSRM with a smaller radius of curvature produces a larger optical deflection, i.e., better system sensitivity. Also, under a given radius of curvature of the MSRM, the system sensitivity can be adjusted by changing the incident angle. A larger incident angle exhibits better system sensitivity/responsivity.