Modeling of a ring confocal resonator field

Abstract

Resonators with an equidistant spectrum are often required in optics. One of the ways to obtain it is the frequency degeneracy of the resonator mode, which is observed, for example, in the well-known classical (linear) confocal resonator. At the same time, there exist configurations of ring resonators similar to it in terms of their properties—ring confocal resonators. In the first approximation, they can be obtained using several reflecting surfaces in the cavity, at least one of which is concave toroid with radii of curvature in the two main meridional sections ensuring the confocal condition and the degeneracy of the spectrum. Such resonators can be used, in particular, as sensitive elements of miniature optical gyroscopes. We consider the specifics and properties of ring confocal resonators and the conditions necessary to obtain them. Using the modified Fox and Li method to calculate open-ring resonators with astigmatic reflective surfaces, the field of the ring confocal resonator is simulated.