Dynamical studies of non-degenerate two-wave mixing.

We experimentally study non-degenerate two-wave mixing with a harmonically varying frequency shift in dark ruby and colloidal media and compare the results to theoretical models for the detailed process in these two very different physical systems. Excellent agreement is found for both the radiative decay in ruby as well as the particle diffusion driven relaxation of nano-particle colloidal media. The results show that there is a universal asymmetry in the oscillating energy exchange waveform which arises from symmetry-broken grating dynamics of the in-phase and out-of-phase gratings. [ABSTRACT FROM AUTHOR]