Thermal behaviour modelling of tapered optical fibres for scanning near-field microscopy

A simple model allowing the calculation of the thermal field inside a metal-coated fibre tip is presented. The approach has been based on previous temperature measurements which operated in steady state and periodic rate. The model has been inspired from the general theory of heat transfer inside fins, after having divided the taper into a set of layers. The advantage of the method is the possibility to consider any taper shapes. Moreover, any kind of coating thickness and external heat transfer distributions can be considered. As a mean of comparison with some previous works, results obtained for simple configurations are presented. Then, a study of the main governing parameters provides the basic thermal behaviour analysis of optical tips and a comparison with experience is given in order to confirm the validity of our approach.