The present invention relates to a method of using an atomic force microscope comprising exciting natural lower and higher vibration modes of a microlever (M) placed on a sample, and analyzing the variation of one variable of a first output signal (Ai cos(ωit−φi)) representative of the response of M to the excitation of the lower mode, with respect to the variation of a parameter influenced by one variable of a second output signal (Aj cos(ωjt−φj)) representative of the response of M to the excitation of the higher mode, and/or analyzing the variation of one variable of a second output signal (Aj cos(ωjt−φj)) representative of the response of M to the excitation of the higher mode, with respect to the variation of a parameter influenced by one variable of a first output signal (Ai cos(ωit−φi)) representative of the response of M to the excitation of the lower mode.