In part one, contact modes were described. In this section phase contrast imaging, sometimes called non-contact imaging, is described. In this mode the probe is moved up and down as it is rastered over the surface in a similar manner to force modulated contact mode. This is illustrated below.

However, this is a resonance mode in which the cantilever is vibrated at its resonance frequency and the feedback loop is set to control the amplitude of the oscillation at the tip. As the tip approaches the sample this amplitude is reduced through its interaction with the sample surface. A % attenuation is set and maintained constant as the tip is rastered over the sample. The image is constructed from changes in the phase angle, which are related to the properties of the sample beneath the tip. The interpretation of the phase image is complicated because the factors governing its magnitude include the viscoelastic, adhesion and frictional properties of the tip and sample. Surface contamination can also play a part. Its great advantages is that it tends not to damage even soft samples like polymers and can provide images with good contrast.

This is illustrated in the images shown below of an isotactic polypropylene/Kraton blend.