Asylum Research has announced that its Cypher AFM is routinely achieving resolution of atomic-scale point defects in liquid.
While scanning tunnelling microscopes have routinely demonstrated point defect resolution since their invention, this gold standard of true atomic resolution has been more elusive in AFM.
Many commercial AFMs can routinely image atomic lattices in ambient and liquid conditions, but the lack of point defects has led most researchers to conclude that the contact areas are typically several atoms across.
More recently, instrumental improvements have brought true atomic resolution to ultra-high vacuum (UHV) AFM.
Achieving true atomic resolution under ambient conditions at the liquid-solid interface brings this resolution to an environment highly relevant for much practical research.
Several technological advancements make this atomic-scale imaging achievement possible.
First is the improved signal-to-noise ratio from the use of ultra-small cantilevers with megahertz resonant frequencies in liquid.
Second, the optical lever detection noise floor has been pushed to 25fm/rtHz, allowing the measurements to remain thermally limited, even with very stiff cantilevers and amplitudes as small as one Angstrom.
These two improvements allow operation with stiff cantilevers and tiny amplitudes, allowing gentle enough imaging that true atomic-sized contact areas are possible.
Finally, Cypher's open-loop noise of 5pm in X, Y and Z allows the stability to image at this scale, even on a scanner with a 30um lateral range.
