Cascaded degenerate four-wave mixing generation in thin-film lithium tantalate microdisk cavity

On-chip efficient nonlinear functions are instrumental in escalating the utilities and performance of photonic integrated circuits, especially for a wide range of classical and quantum applications, such as tunable coherent radiation, optical frequency conversion, spectroscopy, quantum science, etc. Here, we fabricated a $Z$-cut lithium tantalate on insulator (LTOI) microdisk with high quality ($Q\ensuremath{\sim}{10}^{6}$) factors. Cascaded three- and four-wave mixing generation simultaneously were achieved in the LTOI microdisk cavity, due to the high $Q$ factor with a strongly confined light field, relatively large nonlinear coefficient, and optical damage threshold of the LTOI microdisk. The strict mode phase-matching condition and the second-harmonic efficiency of the whole three-wave mixing processes were analyzed. Our work shows that the LTOI microresonators with the high $Q$ factor and its high optical damage threshold and wide transparency range can support a variety of on-chip optical nonlinear processes, which heralds its application potential in integrated nonlinear photonics.