| We discuss the propagation of electromagnetic waves in media that are designed to have a complex, PT-symmetric refractive index. The mathematics is governed by an analogue Schroedinger equation in which the longitudinal distance takes the role of time. In particular we show how the method of stationary states can cast light on both cases: when the PT symmetry is conserved, and at the critical point where symmetry breaking first occurs. In the first case we can make use of the similarity transformation to an equivalent Hermitian problem, and in the second the role of Jordan blocks and the associated Jordan functions is investigated. |
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