PACS:42.50.Gy, 42.60.Da, 42.62.Fi (all) DOI:10.1070/PU1975v017n04ABEH004422 URL: https://ufn.ru/en/articles/1975/4/e/ Citation: Letokhov V S, Chebotaev V P "Resonance phenomena in saturation of absorption by laser radiation" Sov. Phys. Usp.17 467–491 (1975)