PACS:01.50.My, 42.65.Jx, 78.20.Nv (all) DOI:10.1070/PU1987v030n03ABEH002823 URL: https://ufn.ru/en/articles/1987/3/f/ Citation: Ageev L A, Kuleva M G, Yarovaya R G "A simple demonstration experiment in nonlinear optics (Thermal defocusing of laser radiation)" Sov. Phys. Usp.30 284–285 (1987)