Trends of structural modifications and phase composition occurring in In4Se3 thin films and In4Se3-In4Te3 epitaxial heterojunctions under laser irradiations have been investigated. Dynamics of the layer structure modification, depending on laser modes, i.e. pulse duration tau = 2-4 ins, irradiation intensity I-o = 10-50 kW/cm(2), number of pulses N = 5-50, was studied by electron microscopy. An increase in laser influence promotes enlargement of the layer grains and transformation of their polycrystalline structure towards higher degree of stoichiometry. As a result of laser solid restructuring heterojunctions of In4Se3-In4Te3, being photosensitive within 1.0-2.0 mu m and showing fast time of response, have been obtained. Laser modification of structure enables one to optimize electrical and optical properties of functional elements on the base of thin films and layers of In4Se3, In4Te3, widely used as infrared detectors and filters. (C) 2007 Elsevier B.V. All rights reserved.