Generation of 280 THz-spanning near-ultraviolet light in lithium niobate-on-insulator waveguides with sub-100 pJ pulses

Integrated optics has weak ultraviolet and near-ultraviolet (NUV) light conversion due to its strong material dispersion and large propagation losses. To reach this spectral range, we use non-centrosymmetric waveguides that convert near-infrared (NIR) supercontinuum light into broadband NUV light. We measure a 280 THz span that reaches the upper frequency of 851 THz (352 nm) in a 14-mm long rib waveguide of lithium niobate-on-insulator, with an engineered dispersion for supercontinuum generation in the NIR range. The results on broadband NUV signals promote integrated optics for spectroscopy and fluorescence applications such as atomic clocks and chemical sensors.