Comparative study of different process steps for the near-field optical probes manufacturing

This paper deals with different methods for the manufacturing of near-field optical probes with nanometric aperture. After the wet chemical etching of the fiber, two metallization processes are compared: the well-known thermal evaporation versus the novel arrangement of plasma sputtering. Further, it is reported an original controlled nano-indentation in the smooth softness surface to produce the apex aperture of the tapered fiber. These apertures present thin protrusions, but they show good optical and topographic resolutions. Besides, the probe sensitivity is discussed with respect to the multi- and single-mode of the primary optical fiber for imaging sub-wavelength dimension objects in the collection mode.