Scattering-type multi-probe scanning thermal microscope based on near-field thermal radiation

Abstract

As one of the most potential applications of near-field thermal radiation, near-field scanning thermal microscope has its own advantage compared with commercial near-field scanning optical microscope, which takes the thermally excited near-field radiation as light source and does not need external illumination. However, the signal of near-field scanning thermal microscope is very weak. Ones have to heat the tip or sample to improve the signal, or apply a sensitive detector. In this work, we describe a scattering-type multi-probe scanning thermal microscope (s-m-SThM) based on near-field thermal radiation which is configured with multi-probe to improve the signal, and present a theory to determine its far-field signal. The theoretical model is based on dipole approximation and consider the multibody mutual interactions between the probes and the sample. The results demonstrate that multibody mutual interactions between the probes and the sample can effectively improve the far-filed signal of s-m-SThM. For a three-probe (Au) configuration, the results show that the far field signal has been increased more than 200 times compared with a single probe (Au) configuration. This work will help to improve the applicability of scanning thermal microscope based on near-field thermal radiation.