There are two dynamical stable zones in the operation of solid laser c
ontaining a thermal lens. In this paper, we point out that in the two
stable zones two kinds of dynamical stable states can exist in a laser
resonator: mode-steady thermo-stable state and power-steady thermo-st
able state. They are different from each other in general. The operati
ng conditions for power-steady thermo-stable state are presented. A cw
Nd:YAG thermo-stable resonator operating in power-steady states has b
een designed, and 40 W TEM00 output power in 1.06 mum is obtained expe
rimentally.