Influence of circularly polarised light on the magneto-optical second harmonic generation in the iron garnett film derivatives

It was established a substantial decrease of the output magnetization-induced SHG for the 7 ns Erbium glass laser (λ = 1535 nm) with pulse repetition about 20 Hz for Yttrium Garnett alloy derivatives. For the study we have used circularly polarised light of the Q-switched the Nd-YAG laser (λ = 1064 nm) with pulse energy about 20 mJ. We have studied derivatives of iron garnett films deposited on the crystalline Gd3Ga5O12 (1 1 1) substrates. The experiment was done for the diagonal xx SHG components, where the direction x corresponds to the crystallographic x-axis in the Gd3Ga5O12 (1 1 1) substrate plane. Varying the direction of the applied magnetic filed by sign it was established that magnetic contrast determining the SHG difference for two opposite magnetic field directions disappears at pump power of the circularly polarized light equal to about 0.6 GW/cm2.