Force Modulation

Contrast in force modulation is dependent on the spring constant of the cantilever which must compliment the pliancy of the two materials being contrasted.  The spring constant should be close to or in between the pliancy of one or the other material.  In this way, the tip will indent into one material more than the other providing good force modulation image contrast.  These force modulation cantilevers have a mid-range spring constant which provides a good starting point for force modulation imaging.