Abstract
Goran Lindblad was one of the pioneers of what is called now Quantum Thermodynamics. From this vast and rapidly developing field we have selected a sample of results concerning quantum open systems described by Markovian Master Equations of the Lindblad (Gorini-Kossakowski-Sudarshan) type, which are applied to models of lasers. One can study their thermodynamics using the properties of quantum relative entropy, also introduced by Lindblad.