This page explains the functioning of lasers, including their reliance on quantum processes for coherent light generation and the importance of population inversion. It addresses the efficiency of thr...This page explains the functioning of lasers, including their reliance on quantum processes for coherent light generation and the importance of population inversion. It addresses the efficiency of three- and four-level lasers, challenges in building high-energy lasers, and concepts such as laser oscillators and diodes. The text also covers the impact of resonant frequencies, line broadening effects, and molecular collisions on laser operations.