A scanning force microscope with a fiber-optic-interferometer displacement sensor

We present a simple optic-fiber displacement sensor for a scanning force microscope (SFM). The design minimizes the alignment difficulties after a cantilever is changed and is easily adaptable to tube scanners so very compact SFM designs should be possible for imaging at low temperatures or in strong magnetic fields. We also provide a theoretical analysis and results to show that the sensitivity of the device can be improved by increasing the reflectivity of the fiber end. The increased sensitivity makes it possible to work under fluids.