Optimizing the Laser Spot Positioning on Tailored Microcantilevers Used in Atomic Force Microscopy

The advancement of dynamic and multifrequency atomic force microscopy (AFM) necessitates leveraging the frequency response of cantilevers when it is in contact with the specimen surface. By capturing the vibration response of the cantilever, it becomes possible to map and measure the local properties of materials. Utilizing higher oscillation modes of microcantilevers holds the potential for increased sensitivity in imaging and characterizing advanced AFM techniques. Modifying the geometry of the cantilever can enhance its frequency response by aligning the higher eigenfrequencies with the fundamental frequency. The crucial aspect across all AFM techniques is probing the cantilever’s response. Due to the varying shapes of cantilever vibrations for different eigenfrequencies, precise detection of the vibrational mode shape is essential to accurately quantify material properties. This detection heavily relies on the size and placement of the focused optical spot. In this article, we investigated and compared the impact of laser positioning on the captured dynamic responses of both standard and modified microcantilevers. Subsequently, we assessed the imaging performance of different eigenmodes of tailored modified cantilever by locating laser spots at different positions of the cantilever surface. Our study offers guidelines for optimizing the spot position to enhance quantification and imaging using tailored cantilever eigenfrequencies.