Scanning Near-Field Optical Microscopy and Scanning Thermal Microscopy

The development of the scanning tunneling microscopy has led to the development of related techniques which include the scanning near-field microscopy (SNOM) and the scanning thermal microscopy (SThM). These techniques provide sample information in addition to the simultaneously obtained topography. With SNOM normal optical microscopy contrast mechanisms (adsorbance, fluorescence, polarization, etc.) can be used. The principles and design of a SNOM are presented. Subwavelength resolution (better than λ/20) is demonstrated. In SThM, the contrast is provided by temperature and thermal conductivity. The design of a resistive thermal probe is described. Several operating modes are described and image contrast due to thermal conductivity is demonstrated.