A Low Temperature Scanning Force Microscope with a Vertical Cantilever and Interferometric Detection Scheme*

We have developed a fiber-optic interferometry system with a vertical cantilever for scanning force microscopy. A lens, mounted on a Pan-type walker, was used to collect the interference signal in the cavity between the cantilever and the single mode fiber. ~This vertical geometry has several advantages: (1) it is directly sensitive to lateral forces; (2) low spring constant vertical cantilevers may allow increased force sensitivity by solving the ``snap-in'' problem that ~occurs with soft horizontal cantilevers. ~We have sharpened vertical cantilevers by focused ion beam (FIB), achieving a tip radius of 20 nm. ~We will show test results of a magnetic force microscope (MFM) with this vertical cantilever system.