Microsphere embedded in cantilever opens the AFM to high resolution optical microscopy

Summary form only given. The combination of the AFM technique and the sphere-mediated microscopy (SMM) [1] opens a new opportunity to the Atomic Force Microscopy (AFM). With the help of a tipless AFM cantilever is possible to place and scan a microspheres (MS) close to the surface. From the optical point of view, when a MS is close to a surface act as high NA nanolenses whose optical characteristics define the maximum attainable resolution.We performed a detailed measurement of the spatial resolution in SMM by imaging a calibration target made of gratings with different periodicity. Images of the test gratings with and without the microsphere allowed a full characterization of the spatial frequency response of our microscope (modulation transfer function or MTF) and the consequent quantitative determination of the enhancement in resolution induced by the microsphere[2].