Use of vector diffraction theory in theoretical and experimental investigation of SNOM tips

An approach to the optical investigation of probes for scanning near-field optical microscopes (SNOM tips) and recognition of their near-field parameters by far-field measurements is considered. The comparison of approximate calculations of vector light field diffracted by a subwavelength aperture with more rigorous calculations of the light field passing through tapered end of a SNOM tip is presented. A numerical iterative procedure of the SNOM tip aperture reconstruction by the analytical continuation of the emerging light Fourier spectrum is presented. The approach is based on the use of plane waves covering a wide range of spatial frequencies. The results of experimental measurements and far-field data treatment with the definition of a subwavelength aperture are discussed.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.