Optical fiber atomic force microscope with photonic crystal force sensor

An atomic force microscope (AFM) integrated directly on the facet of a standard single-mode optical fiber is designed, fabricated, and tested. High resolution force sensing is achieved with a Fabry-Perot interferometer made of two photonic crystal (PC) mirrors separated by silicon springs. The device is fabricated with standard MEMS techniques and assembled on the facet of a single mode optical fiber by focus ion beam (FIB) welding and OmniProbe manipulation. We demonstrate that topographic and tip-sample interaction force information can be extracted from its reflected light. The force curve measurement has a resolution of 10pN/Hz^0.5 in a drastically smaller footprint than traditional AFMs, which can enable in-vivo AFM imaging.