KINETICS, MORPHOLOGY AND PULLING REGIMES FOR SENSING TIPS IN NEAR-FIELD MICROSCOPY

The spatial resolution provided by near-field scanning optical microsc opes depends critically on the shape and size of the sharpened tip of the optical fiber used as a source of light or sensing element. The fa brication of a tip by the commonly used heating and pulling method is examined. It consists of an initially pulling and rupture followed by a cooling and relaxation. Different thermal and mechanical regimes are possible. The presented analysis leads to a deeper physical understan ding of these processes and suggests avenues for technical improvement s.