Effects of losses and phase mismatch on transient processes in optical parametric amplification through three-wave mixing of ordinary and backward electromagnetic waves

Three-wave mixing of ordinary electromagnetic waves and the waves with contra-directed phase and group velocities in the pulsed regimes is shown to be accompanied by unusual transient processes. We have investigated how attenuation and phase mismatch of the coupled waves in the metamaterials change the properties of parametric amplification and the threshold intensity of the pump wave which is of critical importance.