Adventures in attonewton force detection

We report detection of forces as small as 1.4 × 10-18 N in a 1 Hz bandwidth using ultrathin silicon cantilevers operating at liquid helium temperatures. Cantilever fabrication, the importance of surface cleanliness and various measurement issues are discussed. Tip-surface interactions are described, including the detection of single electron trapping-untrapping events. Applications of attonewton force detection for single spin magnetic resonance force microscopy (MRFM) and ultrasensitive magnetometry are discussed. © Springer-Verlag 2001.