Photonic Force Microscopy: from FemtoNewton force sensing to Ultra-sensitive Spectroscopy

Photonic force microscopy is a scanning probe technique based on the use of optical tweezers. An optically trapped probe particle is scanned over a surface or in a three-dimensional structured environment to probe force interactions. This technique is capable of force sensing at the sub-piconewton level with spatial reso- lution in the nanometre range depending on the dimensions of the trapped particle used as probe. Here we review some recent advances in the technique focussing on applications based on the use of linear nanostructures, bio-force sensing and imaging, and integration with ultra-sensitive spectroscopy such as Raman tweezers.