Laser physics

Subjects related to the population inversion in active media are discussed, taking into account some general aspects, optical pumping in the case of solid-state lasers, organic dye lasers, gas lasers with wideband optical pumping, pumping by self-maintained electric discharge in rarefied gases, electro-ionization lasers, gasdynamic lasers (thermal pumping), chemical lasers, and plasma lasers (recombination pumping). The formation of the radiation field in a laser resonator is considered, giving attention to general conditions, an optical resonator and laser radiation, open resonators, lens waveguides and open resonators (geometrical optics approximation), the detuning of an open resonator, the analysis of open resonators on the basis of the Fox-Li iterative method, Gaussian beams, unstable resonators, frequency selection, waveguide resonators, and optical radiation in a thin-film waveguide. The dynamics of laser processes are also examined. The topics explored are related to free generation, an unstable resonator laser, giant pulse generation, and longitudinal mode locking.