Dr. Zhao won the Excellence Teaching Award in the 2025 SUSTech teaching competition.

On December 20, 2024, Mr. Jiazhao He, an undergraduate student of LICONLAB, was honored as a representative of the Special Prize of School Motto "Advance" Series Scholarship in recognition of his outstanding achievements in academic research, innovative practice, social service and growth. Congratulations to He Jiazhao!

In this work, we uncover the pivotal role of the extinction ratio in FWM processes through integrated innovations in ring-bus coupler design. We demonstrate that the extinction ratio of the cavity resonance directly dictates FWM efficiency. By optimizing the coupling conditions to achieve high extinction ratios (6.6 dB), we realize an 11.95 dB enhancement in FWM efficiency compared to low-extinction-ratio cavities (3.3 dB), in excellent agreement with theoretical predictions. These findings highlight the importance of designing microring resonators at critical coupling conditions to maximize nonlinear conversion efficiency.

We demonstrate a fast-response infrared lead sulfide (PbS) QD photodetector operating at 1550 nm wavelength. We systematically characterize the absorption properties of the QD solution, QD film, and the final fabricated photodetectors. Our photodetector exhibits a responsivity of 2.61 × 10−3 A/W at zero bias, which is further boosted to 0.16 A/W at −1 V bias, with photoresponse spanning the telecom S- and C-bands. The photodetector features a -3 dB bandwidth of 4 kHz and a rapid rise time of 86.7 µs. For the first time, we showcase the photodetector in acetylene gas absorption spectroscopy and high-Q tantalum pentoxide microresonator transmission spectrum characterizations, and achieve excellent agreement with the results measured by commercial detectors.

Here, we explore gallium phosphide (GaP) for supercontinuum generation, leveraging its strong second-order and Kerr nonlinearities, broad optical transparency, and low two-photon absorption at telecom C-band. We report the octave-spanning supercontinuum generation in a sub-millimeter GaP waveguide. The generated supercontinuum, when excited with transversely magnetically polarized light, features a gap-free spectrum and high coherence. Furthermore, our GaP waveguide demonstrates a figure of merit of 43.56 THz/mm/kW, which is the highest reported figure of merit among various integrated photonic platforms operating in the normal dispersion regime. We also observe and analyze the rich underlying physical mechanisms of multiple second harmonics. These results highlight the exceptional versatility of the GaP-on-isolator platform for broadband nonlinear photonics.

In this work, we demonstrate, for the first time, dual-polarization four-wave mixing (FWM) spectral translation in a Ta₂O₅ microring resonator. The device features a trapezoidal waveguide geometry optimized to support both TE₀₀ and TM₀₀ fundamental modes with intersecting dispersion curves at 1548 nm. The fabricated resonator exhibits high loaded quality factors of 1.78 × 10⁵ (TE₀₀) and 1.46 × 10⁵ (TM₀₀), and low propagation losses of 1.85 dB/cm and 1.96 dB/cm, respectively. The device also shows excellent thermorefractive stability, with temperature-dependent wavelength shifts (TDWS) as low as 7.19 pm/K (TE₀₀) and 7.49 pm/K (TM₀₀). The difference of the TDWS enables accurate resonance alignment via chip temperature tuning. Under on-chip pump powers of 14.13 dBm (TE₀₀) and 13.87 dBm (TM₀₀), FWM conversion efficiencies of –36.15 dB and –35.29 dB are achieved at the same pump wavelength. These results underscore the potential of Ta₂O₅ for doubling spectral capacity, including polarization-multiplexed optical communication and dual-comb generation for spectroscopy.