Influence of active-medium properties on high-power solid state laser beam characteristics

In order to describe the transversal mode construction in a real laser resonator, a mathematical model was investigated. The analysis use Kirchhoff-Fresnel diffraction equation and amplification processes in the active medium, that was supposed as sum of thin discs with gain and losses constants on every disc's length. Influence of additional phenomenon on laser beam characteristics, as phase-shift caused by active medium thermal induced refractive power and curvature of the resonator mirrors were considered.