Figure 2.

Stimulated-photon echo signal of CA–N₃⁻, Hb–N₃⁻, and Hb–CO plotted against delay time τ for selected delay times T together with global fits (solid lines). The signals in the k_α (solid symbols) and the k_β (shaded symbols) directions are both shown. The k_α signal at +τ is identical to the k_β signal at −τ, and the shift between both signals is a measure of inhomogeneity at time T. The asymmetry of the signals with respect to τ decays with time T.