Dynamics of transient probe beam amplification via coherent multiwave mixing in a local nonlinear medium-nematic liquid crystal

The dynamics of the transient thermal-grating-mediated probe-beam amplification effect in a nematic liquid crystal film is studied with the use of millisecond laser pulses. These experimental observations and the accompanying transient multiwave mixing analysis show that peak probe gain can occur at various locations within the grating decay time; the higher the induced index change, the sooner will peak gain occur.>