Thermal imaging at the nanoscale

We develop a theoretical description of the heat flux between a miniaturized sensing tip and a structured surface of different temperature at nanometer distances. A near-field effect known as “photon tunneling” then allows one to obtain images of the surface. Because such a “photon tunneling microscope” is sensitive to the electromagnetic local density of states, the information acquired in this manner differs from that accessible to a conventional electron tunneling microscope, which maps the electronic local density of states.

 

This work is performed in close collaboration with the experimental Energy and Semiconductor Research Group headed by Jürgen Parisi. Under the guidance of Achim Kittel, this group has developed a functioning Near-Field Scanning Thermal Microscope (NSThM), which has the unique capability of assessing the extreme near-field regime. Our joint Oldenburg Project aims at a comprehensive understanding of the working principles of this novel instrument. The figures below show a theoretically reconstructed (left) and an experimentally measured (right) thermal image of a nanostructured surface.

Comparision of theory and experiment