Fluctuational electrodynamics for nonlinear media
4th Institute for Theoretical Physics, Universität Stuttgart - Stuttgart, Germany and Max Planck Institute for Intelligent Systems - 70569 Stuttgart, Germany
Received: 20 June 2016
Accepted: 31 August 2016
We develop fluctuational electrodynamics for media with nonlinear optical response. In a perturbative manner, we amend the stochastic Helmholtz equation to describe fluctuations in a nonlinear setting, in agreement with the fluctuation dissipation theorem, and identify the local (Rytov) fluctuations of electric currents. We show how the linear response (the solution of the scattering problem) of a collection of objects is found from the individual responses, as measured in isolation. As an example, we compute the Casimir force acting between nonlinear objects which approaches the result for linear optics for large separations, and deviates for small distances.
PACS: 12.20.-m – Quantum electrodynamics / 42.65.-k – Nonlinear optics / 42.50.Lc – Quantum fluctuations, quantum noise, and quantum jumps
© EPLA, 2016