General Properties of 3/2ω₀ and 2ω₀ Harmonics Emission from Laser Driven Plasmas

Using a simple model based on the conversion of electron plasma waves into electromagnetic waves through a process of parametric interaction of four waves, the general properties of the  3/2ω₀ emission and the 2ω₀ emission generated by the interaction of a Gaussian laser pulse with homogeneous plasma are studied. Some known characteristics of these emissions are reproduced within this model and compared to some experimental works. In particular, the two-wing structure of the emitted spectrum, the double-beam structure, the angular distribution and the conversion efficiency are obtained. Moreover, it is found that, the intensity of the backward beam is almost double of that of the forward beam in both emissions, while this later is narrower in the case of the 3/2ω₀ emission.