Effect of laser beam focusing point on AFM measurements

The optical beam deflection method, which is used in AFM to obtain surface images, may distort the resulting image. The flexible and long cantilever is easily overdamped by the laser radiation pressure, resulting in steady deflection of the cantilever (<1 nm). This deflective force distorts the image and influences the force-distance (F-D) curve. The present study investigated the effect of laser radiation pressure on image distortion. As a proof-of-concept test, two grating samples (with step heights of 150 and 18 nm for TGX01 and TGZ01, respectively) were examined with an NSC36 series cantilever in air and water media.