1.双光梳与双频激光技术及应用

主要开展基于共腔结构的双光梳锁模激光器与双频率激光器，基本思想是在同一个谐振腔中产生两个激光振荡，利用共腔结构抵消共模噪声，从而产生结构紧凑且具有较高互相干性的双频激光或双光梳。开发新型全固态与光纤双光梳锁模激光器；提升共腔双光梳锁模激光器的互相干性与频率可控性，以及在波长、功率、脉宽、紧凑性、成本、鲁棒性等方面的性能；拓展双光梳锁模激光器的应用范围，包括痕量气体检测、环境监测、薄膜检测、超快光谱、激光雷达、光纤传感、光谱成像、双源极紫外高次谐波等前沿领域。

2.极端非线性激光物理与技术

研究少周期强激光光源技术及其与物质的相互作用，重点研究固体高次谐波产生及其增强技术，开发新型超快光谱技术，为材料科学与基础物理提供新的探测手段。

1. R. Tang; Z. Luo; H. Xie; P. Ying; S. Xu; H. Liu*; J. Bai, "Polarization-multiplexed Dual-comb Yb:CALGO Laser and its Noise Investigation," Journal of Lightwave Technology, 2024: 1-7.

2. R. Tang; Z. Luo; P. Li; P. Ying; H. Xie; S. Xu; J. Bai*; H. Liu*, "Dual-comb Yb:CALGO laser with a polarization multiplexed cavity and pump," Optics Express, 2024, 32(25): 44829-44840.

3. 宋鹏枼, 陶家宁, 应鹏润, 靳昊澍, 谢海洋, 侯磊, 许思源, 刘辉*, "基于全正色散光纤锁模激光器的波长可调光谱平顶单腔双光梳," 中国激光 51, 1401009 (2024).

4. R. TANG, Z. LUO, P. LI, P. YING, H. XIE, S. XU, H. LIU*, and J. BAI, "Dual-comb mode-locked Yb:CALGO laser based on cavity-shared configuration with separated end mirrors," (2024).（https://doi.org/10.48550/arXiv.2404.08998）

5. H. Jin, H. Liu*, S. Xu, B. Lu, and J. Bai*, "Polarization-multiplexing of a laser based on a bulk Yb:CALGO crystal," Chinese Optics 16, 1-7 (2023).

6. P. Song, J. Tao, Y. Li, M. Jiang, L. Hou, and H. Liu*, "Polarization‐duplexing of a ytterbium‐doped fiber mode‐locked laser with an intracavity birefringent crystal," Microwave and Optical Technology Letters 65, 1379-1385 (2022).

7. J. Ren, W. Tan, F. Guo, H. Liu*, and H. Chang, "Magnetic field analysis and active compensation system for strontium optical lattice clock in space," Optics and Precision Engineering 30, 1337-1343 (2022).

8. C. Liu, H. Jin, H. Liu*, and J. Bai, "Mode selection and amplification from optical frequency combs by optical injection locking: a numerical study of noise," Applied Optics 61, 5274 (2022).

9. C. Liu, H. Jin, H. Liu*, and J. Bai, "Numerical study of converting beat-note signals of dual-frequency lasers to optical frequency combs by optical injection locking of semiconductor lasers," Chinese Physics B 31, 084205 (2022).

10. J. Ren, H. Liu*, X. Lu, and H. Chang*, "Analysis of Narrow-Line Laser Cooling and Trapping of Sr Atoms in Microgravity Environments," Applied Sciences 10, 4928 (2020).

11. G. Gredat, H. Liu, J. Cotxet, F. Tricot, G. Baili, F. Gutty, F. Goldfarb, I. Sagnes, and F. Bretenaker, "Optimization of laser dynamics for active stabilization of DF-VECSELs dedicated to cesium CPT clocks," Journal of the Optical Society of America B 37, 1196 (2020).

12. G. Gredat, H. Liu*, and F. Bretenaker*, "Thermal phase fluctuations in optically pumped dual-frequency vertical external-cavity surface-emitting lasers for cesium clocks based on coherent population trapping," Journal of Applied Physics 126, 173104 (2019).

13. H. Liu, G. Gredat, S. De, I. Fsaifes, A. Ly, R. Vatre, G. Baili, S. Bouchoule, F. Goldfarb, and F. Bretenaker, "Ultra-low noise dual-frequency VECSEL at telecom wavelength using fully correlated pumping," Optics Letters 43, 1794-1797 (2018).

14. H. Liu, G. Gredat, G. Baili, F. Gutty, F. Goldfarb, I. Sagnes, and F. Bretenaker, "Noise Investigation of a Dual-Frequency VECSEL for Application to Cesium Clocks," Journal of Lightwave Technology 36, 3882-3891 (2018).

15. G. Gredat, D. Chatterjee, G. Baili, F. Gutty, I. Sagnes, F. Goldfarb, F. Bretenaker*, and H. Liu*, "Fully-correlated multi-mode pumping for low-noise dual-frequency VECSELs," Optics Express 26, 26217-26226 (2018).

16. 刘辉, "应用于锶光钟的激光技术及光谱探测研究," 博士学位论文 (中国科学院大学, 北京, 2016).

17. Qinfang Xu, Hui Liu, Benquan Lu, Yebing Wang, Mojuan Yin, Dehuan Kong, Jie Ren, Xiao Tian, and Hong Chang*, "Observation of ¹S₀-³P₀ transition of bosonic strontium in the Lamb-Dicke regime," Chinese Optics Letters 13, 100201-100205 (2015).

18. H. Liu, M. Yin, D. Kong, Q. Xu, S. Zhang, and H. Chang*, "Selection and amplification of a single optical frequency comb mode for laser cooling of the strontium atoms in an optical clock," Applied Physics Letters 107, 151104 (2015).