The influence of strongly absorbing N laser radiation on pores formation on a surface of Si single crystal has be- en investigated using optical microscope and atomic force microscope. After irradiation by the laser and subsequent electrochemical etching in HF acid solution morphological changes of the irradiated parts of a surface of Si were ob- served. At the same time, pores formation on the non- irradiated parts of Si surface took place. The porous part of the Si surface is characterized by strong photolumines- cence in red part of spectra with maximum at 1.88 eV. Suppression of the pores formation by laser radiation is ex- plained with inversion of Si type condition from p to n. This fact is explained by Thermogradient effect - generation and redistribution of the intrinsic defects in gradient of tempe- rature. It was shown that the depth of p-Si layer on n-Si substrate depends on intensity of laser radiation and it in- creases with intensity of laser radiation. The results of the investigation can be used for optical recording and storage of information on surface of semiconductors.