Laser resonators with several mirrors (lenses) have been investigated in a systematic fashion. They have been grouped into classes according to their number n of mirrors/lenses. Stability polynomials, beam waist radii and locations have been obtained for each group up to n = 4. The bow-tie laser resonator is discussed as an example and ways to correct for astigmatism and thermal lens effects in this resonator are presented.
Journal of Optics A: Pure and Applied Optics (print), 2005, Vol 7, Issue 1, p. 7-20