Study of Third Harmonic Generation From Thin Gradient Hf x Al y O z Layers

Third harmonic generation (THG) from multiple thin layer structures has proven its capability to reach conversion efficiencies up to the percentage level [1] , becoming an interesting alternative to the cascaded third harmonic generation. However, such multi-layer structures need to be carefully optimized by computer algorithms. Here, we present a study of a single amorphous Hf x Al y O z layer with varying thickness. The advantage of ternary mixture materials such as Hf x Al y O z is the tunability of the bandgap, which directly influences the nonlinear susceptibility χ (3) . In comparison to previous works, where only layers of specific thickness or theoretical models were studied [2] , [3] , we present both, continuous experimental measurements and theoretical studies of the same sample.