I recently asked this question about the non-axial photons of a laser cavity. While doing further research on the subject, I read that exploiting the paraxial photons by having one mirror of the laser cavity be flat and the other be curved enhances stimulated emission. An example of this seems to be the "hemispherical" cavity geometry in the figure in user A. P. answer:
However, it is also said that this produces a (more) divergent beam.
How is it that such cavity geometries produce a more divergent beam, compared to if we had just two flat mirrors? For instance, if the flat mirror in the image above is less than 100% reflective, and so is the mirror from which the beam escapes the cavity, should it not actually be focused at a smaller point (that is, result in a less divergent beam), rather than a larger point (that is, result in a more divergent beam)? Or is it because, beyond some point, the two rays in the image above "cross over" (I think this is point is called the focal point?), and so the beam actually begins to diverge beyond this point?