A method for localization of a light source near the interface of two media is described. The method is based on an optical analog of tunnel effect when the radiation source is at the distance smaller than the wavelength from the interface. Application of the tunnel effect permits to obtain high resolution. The developed method was used to determine the localization of a bacterial luminescent system. It has been found that the sources of bioluminescence are located at thin subsurfase lager with width about 70 nm. This result is in favour of the peripheral (periplasmatic or membrane) localization of the bacterial luminescent system. This method makes it possible to investigate processes pelated to light radiation (luminescence, fluorescence and other optical processes) in a thin surface layer of various biological and physical objects.