Scanning Electron Microscopy (SEM) image of an electrochemically etched gold wire for atomic force microscopy. These tips are suited for Tip Enhanced Raman Spectroscopy (TERS).
A smooth surface is important for TERS to achieve a strong nearfield by surface plasmon resonances only at the apex of the tip.
High tip curvature to enhance the lightning rod effect.
Light microscopy image of a gold tip.
Tapping mode AFM scan (phase contrast) on a polished periodically poled lithium niobate crystal. The tip has been deliberately decorated with dipole molecules and Coulombic interaction is causing the contrast along the domain walls between the out-of-plane polarized domains.