Kramers-Kronig Relations in Optical Materials Research

TheKramers-Kronigrelationsconstitutethemathematicalformulationofthe fundamental connection between the in-phase to the out-of-phase response of a system to a sinusoidal time-varying external perturbation. Such connection exists in both classical and quantum physical systems and derives directly from the principle of causality. Apart from being of great importance in high energy physics, statistica...