Conservation of energy in coherent backscattering of light

TL;DR

This paper demonstrates that energy conservation in coherent backscattering of light is maintained through an energy cutback at other angles, supported by experimental data and a theoretical model involving interference effects.

Contribution

It provides the first comprehensive experimental and theoretical analysis showing energy conservation in coherent backscattering, resolving apparent violations.

Findings

Energy enhancement is balanced by energy cutback at other angles.

Experimental data confirms the theoretical model.

Interference effects explain energy conservation in multiple scattering.

Abstract

Although conservation of energy is fundamental in physics, its principles seem to be violated in the field of wave propagation in turbid media by the energy enhancement of the coherent backscattering cone. In this letter we present experimental data which show that the energy enhancement of the cone is balanced by an energy cutback at all scattering angles. Moreover, we give a complete theoretical description, which is in good agreement with these data. The additional terms needed to enforce energy conservation in this description result from an interference effect between incident and multiply scattered waves, which is reminiscent of the optical theorem in single scattering.