Perturbation Theory Generalized to Arbitrary (p,l) Modes in a Fabry-Perot Resonator (Letters)

The first-order perturbation calculation that was carried out to include the effects of the usually neglected delta²psi / delta z² term in the wave equation for pure radial modes (l = 0) is generalized to the case of arbitrary p,l modes. The result, although requiring more algebra, is similar to that of the l= 0 case; the correction term is a monotonically increasing function of both p and l, and reduces to the original expression as l --> 0.