Equivalent optical resonators.
1450 APPLIED OPTICS / Vol. 23, No. 10 / 15 May 1984 concerning the significance of these equivalent systems and the different g-parameters characterizing a lens-type reso­ nator. It is the aim of this Letter to discuss briefly the meaning of an equivalent resonator and the relations between g-parameter, mode structure, and beam divergence. To understand the misinterpretations, some details of resonator theory have to be remembered. Let us start with the well-known stable spherical resonator. For the sake of simplicity a 1-D system is considered. The integral equation reads