As a material that contains both large \(\chi^{(2)}\) and \(\chi^{(3)}\), lithium niobate has lead to variaty investigation and application on nonlinear optics. Recent development on the thin-film lithium niobate allows micro-structure lithium niobate device, which can enhance the nonlinear effect to a new regime.

Our group works on investigating the novel nonlinear optics phenomena on thin-film lithiumniobate, including periodic-poled lithium niobate (PPLN) for efficient frequency conversion, electro-optic frequency comb, Kerr frequency comb, etc

EO frequency comb: 

• Single-resonator EO comb [Mian Zhang, et al. Nature 568, 373 (2019)]: We demonstrate the generation of broadband electro-optic frequency combs with a record-high bandwidth (one orders of magnitude higher than previous EO comb). 

• Coupled-resonator EO comb [Yaowen Hu, et al. Nature Photonics 16, 679 (2022)]: We further demosntrate high-efficiency and broadband electro-optic frequency combs, featuring a 100-times higher conversion efficiency and a 2.2-times broader bandwidth compared to previous our state-of-the-art EO comb [Zhang, et al. Nature 568, 373 (2019)]. We also demonstrate the device is an on-chip femtosecond pulse source with pulse duration of 336 fs.

• Femtosecond pulse source using time-lens [Mengjie Yu, et al. arXiv 2112.09204 (2021)]: We demonstrate femtosecond pulse source with pulse duration of 520 fs using time-lens system.