Light scattering by radiation fields: The optical medium analogy

¹ Istituto per le Applicazioni del Calcolo “M. Picone”, CNR - I-00185 Rome, Italy, EU
² ICRA, “Sapienza” University of Rome - I-00185 Rome, Italy, EU
³ INFN sezione di Firenze - I-00185 Sesto Fiorentino (FI), Italy, EU
⁴ Astronomical Observatory of Torino, INAF - via Osservatorio 20, I-10025 Pino Torinese (TO), Italy, EU
⁵ Department of Physics, University of Ferrara and INFN sezione di Ferrara - I-44100 Ferrara, Italy, EU
⁶ Physics Department, “Sapienza” University of Rome - I-00185 Rome, Italy, EU
⁷ INFN - National Laboratories of Legnaro, I-35020 Legnaro (PD), Italy, EU

Received: 27 February 2013
Accepted: 5 April 2013

Abstract

The optical medium analogy of a radiation field generated by either an exact gravitational plane wave or an exact electromagnetic wave in the framework of general relativity is developed. The equivalent medium of the associated background field is inhomogeneous and anisotropic in the former case, whereas it is inhomogeneous but isotropic in the latter. The features of light scattering are investigated by assuming the interaction region to be sandwiched between two flat spacetime regions, where light rays propagate along straight lines. Standard tools of ordinary wave optics are used to study the deflection of photon paths due to the interaction with the radiation fields, allowing for a comparison between the optical properties of the equivalent media associated with the different background fields.