Transverse modes and excess noise factor in optical resonators with misaligned mirrors

Summary form only. In this work it is shown in a very general framework that misalignment of optical laser cavities with transversely-varying gain or loss may lead to a substantial enhancement of the transverse excess noise. We consider a general linear optical resonator with one or two tilted end mirrors containing aligned paraxial optical elements and transversely-varying gain or loss elements that can be described by a complex-valued one-way ABCD matrix. General expressions for the transverse modes, in terms of complex-valued off-axis Hermite-Gaussian modes, and corresponding eigenvalues are analytically derived by solving the Kirchhoff-Fresnel round-trip integral equation including mirror misalignments.