Abstract: The invention relates to optical microscopy, and more particularly to the methods for photothermal examination of absorbing microheterogeneities using laser radiation. The invention can be widely used in laser technique, industry, and biomedicine to examine transparent objects with absorbing submicron fragments, including detection of local impurities and defects in super-pure optical and semiconducting materials and non-destructive diagnostics of biological samples on cellular and subcellular levels. The object of the present invention is to increase sensitivity, spatial resolution and informative worth when examining local absorbing heterogeneities in transparent objects, as well as to detect the size of said heterogeneities even if said size is smaller than the radiation wavelength used. Said object is achieved by the pump beam irradiation of a sample, the duration of said irradiation not being longer than the characteristic time of cooling of the microheterogeneity observed.

Abstract: The invention relates to optical microscopy, in particular to methods for photothermal examination of absorbent microinhomogeneities using laser radiation sources and can be widely used in laser engineering, industry and biomedicine for examining relatively transparent objects containing submicron impurities, including the detection of local inclusions and defects in ultrapure optical and semiconductor materials and the non-destructive diagnosis of biological samples on a cellular and subcellular level. The aim of the invention is to increase the sensitivity, spatial resolution and informativity of examination of local absorbent microinhomogeinities in transparent objects and to measure said microinhomogeinities even when they are less than the used emission wavelength. The inventive method consists in radiating a sample with a pumping laser beam. The duration of the radiation is equal to or less than a representative time for cooling the examined microinhomogeinity.