atomic force microscope

(a) The sample stage lifts the sample up to the tip of the cantilever until the tip-sample distance is about 2 mm or less, which facilitates safe pre-approach between the tip and the sample. (b) The laser-cantilever is aligned by moving the laser, while detecting the tip and the sample and measuring their positions. (c) The laser beam reflected from the cantilever head is aligned with the center of PSPD based on the electrical signals of PSPD.