STUDY OF TIME-DELAYED 4-WAVE MIXING WITH INCOHERENT-LIGHT IN THE ABSORPTION-BAND OF RUBY

Time-delayed four-wave mixing with incoherent light in the absorption band **4T//2 of ruby has been studied experimentally. Dephasing times have been obtained formally by analyzing the experimental data on the basis of two-level theory at different conditions. Two-level theory fails in the interpretation of the results, and a theory based on a multi-level model has been developed and applied to explain the results successfully. It is shown that T//2 determined on the basis of two-level theory is not the ordinary dephasing time of individual transition but an effective one which reflects the behavior of the total absorption spectrum of the band.