Schematic diagram of the NSOM/IFM instrument. The NSOM fiber is brought into contact with a sample resting on an IFM sensor. The IFM sensor measures the attractive and repulsive normal forces between the tip and sample by maintaining an electrostatic balance of two capacitances C1 and C2, formed by the common plate and identical gold pads fixed on a glass substrate (not shown). This prevents "snap-to-contact" which can occur with compliant AFM cantilevers. The fiber is attached to a piezo that dithers the fiber laterally at its resonance frequency. The piezo also measures any shear force damping (e.g. friction) acting between the tip and sample. Recently, we demonstrated directional control of the lateral motion. Exciting light is launched into the fiber and excites sample fluorescence in the near field. Light is collected in the far-field by an ellipsoidal mirror cavity (not shown).

SPM/Fluorescence microscope

Schematic diagram of the instrument for combining single-molecule fluorescence microscopy with scanning probes. This instrument is optimized for following the dynamics of membrane re-organization and the translocation of biomolecules through membrane pores.