Doppler-like frequency shifts generated by dynamic scattering

Daniel F. V. James, E. Wolf

E. Wolf

It was recently shown that, when light is scattered from a random medium whose response function (e.g., the dielectric susceptibility) has appropriate correlation properties, the spectrum of the scattered light may be frequency shifted with respect to the spectrum of the incident light.1,2 In general the relative frequency shifts produced by this mechanism will be different for different spectral lines. We show that under certain circumstances the relative shifts generated by scattering from appropriately correlated space-time fluctuations may become frequency independent and may be arbitrarily large. This scattering mechanism then imitates the Doppler effect, even though the source, the scattering medium, and the observer are at relative rest with respect to each other.

Peter Jungner, Birger Stahlberg, Stig Stenholm

R. Corbalán, Gaspar T. Orriols, L. Roso +2 more

E. Wolf

Abstract : It is generally taken for granted that the spectrum of light does not change on propagation. This belief is implicit in all spectroscopy. In the last few years it was discovered that while such spectral invariance holds for radiation from commonly used sources it does not hold, in general, because the spectrum of emitted radiation depends not only on the source spectrum but also on the coherence properties of the source. It was found that in some cases the induced changes may be appreciable, possibly resulting in frequency shifts of spectral lines. It has also been demonstrated that similar spectral changes may be produced by scattering on random media whose dielectric susceptibility fluctuations are appropriately correlated. Very recently it was shown that under certain circumstances the frequency shifts generated by dynamic scattering may imitate the Doppler effect, even though the source, the scatterer and the observer are all at rest relative to each other. (emk)

P. L. Knight