Abstract

Various scanning near-field optical microscopes (SNOM) with subwavelength resolutions have been developed during the past ten years.¹ Near-field optical images are obtained by scanning a subwavelength probe (aperture or fiber tip) very close to an illuminated sample surface and detecting the scattered light. Usually, a shear force technique is employed to maintain the probe-surface distance, which allows one also to obtain a topographical image of the surface studied.¹ In such an approach the main problem is to uncouple topographical and optical images so that additional information can be extracted from the optical images. This is especially important for heterogeneous samples, since variations in optical properties can manifest structural changes of sample surfaces. Here we report for the first time results of a systematic study of this problem for the external reflection SNOM.

© 1994 IEEE