光子集成器件以极低的成本和功耗实现覆盖从光源、调制、非线性频率转换、光放大到光探测的全功能单片集成，对光电信息处理系统产生显著而深远的影响，并推动一系列诸如高速通信、人工智能、量子信息，以及精密测量等重大应用领域的持续发展。近年来，铌酸锂薄膜光子器件得益于离子揭膜技术和微纳刻蚀工艺的进步，以宽的工作窗口、低的传输损耗、大的调制带宽、高的非线性光学转换效率和兼容大规模光子集成等优点，在集成光子学领域占据重要一席之地。本文介绍了利用超快激光光刻结合化学机械抛光技术在掺杂有源发光稀土离子的铌酸锂薄膜衬底上实现片上激光与光放大的最新进展，包括在波导放大器中实现了超过20 dB的最大内部净增益，并且在高品质铌酸锂微盘中演示了具有454.7 Hz窄线宽的电光可调谐单频激光器，演示了单片集成的电驱动微环激光器，以及连续光刻方式实现的无源/有源混合集成器件。

Remote or standoff detection of greenhouse gases, air pollutants, and biological agents with innovative ultrafast laser technology attracts growing interests in recent years. Hybrid femtosecond/picosecond coherent Raman spectroscopy is considered as one of the most versatile techniques due to its great advantages in terms of detection sensitivity and chemical specificity. However, the simultaneous requirement for the femtosecond pump and the picosecond probe increases the complexity of optical system. Herein, we demonstrate that air lasing naturally created inside a filament can serve as an ideal light source to probe Raman coherence excited by the femtosecond pump, producing coherent Raman signal with molecular vibrational signatures. The combination of pulse self-compression effect and air lasing action during filamentation improves Raman excitation efficiency and greatly simplifies the experimental setup. The air-lasing-assisted Raman spectroscopy was applied to quantitatively detect greenhouse gases mixed in air, and it was found that the minimum detectable concentrations of CO₂ and SF₆ can reach 0.1% and 0.03%, respectively. The ingenious designs, especially the optimization of pump-seed delay and the choice of perpendicular polarization, ensure a high detection sensitivity and signal stability. Moreover, it is demonstrated that this method can be used for simultaneously measuring CO₂ and SF₆ gases and distinguishing ¹²CO₂ and ¹³CO₂. The developed scheme provides a new route for high-sensitivity standoff detection and combustion diagnosis.

Transparency and perfect absorption are two contradictory terms; a perfect absorber never permits waves to transmit through. However, this statement only remains true in the linear regime, where the nonlinearity has been omitted and the physical system like the perfect absorber is not affected by the incoming waves. Here we experimentally demonstrate an intriguing self-induced transparency effect in a perfectly absorbing optical microcavity, which perfectly absorbs any incoming waves at the low power level, but allows a portion of waves to be transmitted at the higher power due to the nonlinear coupling between the fundamental and its second harmonic modes. Moreover, the asymmetric scattering nature of the microcavity enables a chiral and unidirectional reflection in one of the input ports, this leads to asymmetric and chiral coherent control of the perfect absorption states through phase varying. More importantly, such chiral behaviors also empower the chiral emission of second-harmonic generation with a high distinct ratio in the transparency state. These results pave the way for controllable transparency in a wide range of fields in optics, microwaves, acoustics, mechanics, and matter waves.