Torsion Resonance Mode (TRmode)

Torsion Resonance Mode (TRmode) is a major new technique exclusive to Bruker that measures and controls dynamic lateral forces between the probe tip and sample surface. Utilizing advanced sensing hardware and electronics to characterize torsion oscillations of the cantilever, TRmode enables detailed, nanoscale examination of in-plane anisotropy, and provides new perspectives in the study of material structures and properties. It can also be interleaved with TappingMode AFM to provide complementary lateral and vertical characterization.

In TRmode, the probe is oscillated along the cantilever's long axis, creating a rotational oscillation, i.e., a twisting motion. This oscillation causes a dithering motion of the tip. As the probe encounters lateral forces on the sample surface, the corresponding changes in the cantilever's twisting motion is measured. This twisting can be measured by using a quad-cell position-sensitive photo-detector (PSPD). Contact AFM uses a bi-cell PSPD to measure the vertical deflection of the cantilever, indicating changes in sample topography. With a quad-cell PSPD, both vertical and lateral deflections can be measured.