Towards atomic force microscopy measurements using differential self-mixing interferometry

In this paper, we explore the possibility of joining two measurement techniques that share a similar time frame and that are interested in describing the properties of materials through the study of the micro and nanometric scale. Atomic force microscopy (AFM) is a well established method capable of measuring different material properties by examining the deflection of a micro-cantilever caused by the sample surface force interactions. The cantilever deflection is typically estimated using the optical lever technique which requires a careful alignment of the laser beam and the cantilever. To reduce such problem, we propose the use of differential self-mixing interferometry (DSMI). A test to prove the feasibility of applying the DSMI on an AFM cantilever will be discussed as well as the problems found during the measurement. Preliminary results show that DSMI is capable of following up cantilever sinusoidal displacements with amplitudes in the range of 200 and 100nm which can usually be found in AFM non-contact and taping modes.