Frequency-modulation atomic force microscopy at high cantilever resonance frequencies using the heterodyne optical beam deflection method

We have developed a frequency-modulation atomic force microscope (FM-AFM) with a wideband cantilever deflection sensor using the heterodyne optical beam deflection method. The method enhances the bandwidth of the deflection measurement up to the maximum frequency for the laser power modulation, which can be as high as gigahertz order. The phase and frequency of the cantilever vibration at 5.24 MHz are detected with a deflection noise density of 100 fm/ root Hz. FM-AFM imaging is performed on a Au(111) surface with a high-frequency cantilever. (c) 2005 American Institute of Physics.