Study of dynamic characteristics of multirod plane-plane resonators

Based on the equivalent resonator method,the results of a two rod plane-plane resonator used for high power solid state lasers are extended to multirod plane-plane resonators.The analytical expressions for g*-parameters and equivalent resonator length of a multirod plane-plane resonator are derived.The dynamic characteristics of such a type of resonator are analyzed in detail,and illustrated with numerical examples.It is shown that for two types of multirod symmetric plane-plane resonators,the characteristic curve on the g*-parameter diagram is a straight line passing through the origin.If there is a small discrepance of the thermal focal length of rods,the characteristic curve is no longer a straight line.However,by a suitable adjustment of the distances between the mirrors and rods,the curve becomes again a straight line.Therefore,the discrepance of the thermal focal length can be compensated in such a way,and the relevant mathematical formula is also proposed.