On-chip ultraviolet second-harmonic generation in lithium-tantalate thin film microdisk

The compact and reliable ultraviolet (UV) source has attracted remarkable attention for its potential use in optical measurement systems, high-density storage, biomedical applications. We demonstrate generation by frequency doubling a lithium-tantalate-on-insulator (LTOI) microdisk via modal phase matching. 50-µm-diameter was milled focused ion beam (FIB) followed chemo-mechanical polishing (CMP) to smooth the disk surface edge, Q-factor reaches 2.74×105 visible band. On-chip UV coherent light with wavelength of 384.3 nm achieved, which shows great promise using LTOIs integrated platforms.