Spatiotemporal evolution in femtosecond second-harmonic generation with back-conversion
We systematically investigate second-harmonic generation (SHG) in a lithium triborate (LBO) crystal by a femtosecond laser system (1030 nm, 195 fs, 30 W) with particular emphasis on back-conversion phenomena. For a selected 5 mm thick crystal, an optimal conversion efficiency of 54% is achieved at 18 W input power with beam quality factor M<sup>2</sup> of 1.275 (horizontal) and 1.173 (vertical). Beyond the saturation threshold where back-conversion initiates, spectral broadening, temporal compression and beam quality deterioration emerge, accompanied by decreasing conversion efficiency. Increasing the beam diameter or reducing the crystal length effectively mitigates back-conversion phenomena. These findings establish valuable guidelines for optimizing the performance of femtosecond visible laser sources.
Authors
- Jie Guo (ORCID: https://orcid.org/0000-0002-0814-2025)
- Jianqiu Xu (ORCID: https://orcid.org/0000-0003-4956-5769)
- Luqi Guo (ORCID: https://orcid.org/0000-0002-2513-9485)
- Zhihua Tu (ORCID: https://orcid.org/0000-0002-4505-2336)
- Xiaoyan Liang (ORCID: https://orcid.org/0009-0009-9873-4080)
- Zichen Gao (ORCID: https://orcid.org/0000-0002-4403-585X)
- Jinfeng Li
- Pukai Xue
Institutions
- Tongji University (CN)
- Chinese Academy of Sciences (CN)
- Shanghai Zhangjiang Laboratory (CN)
- University of Chinese Academy of Sciences (CN)
Publication Details
- Journal
- Optics Express
- Published
- 2025-06-17
- DOI
- https://doi.org/10.1364/oe.566024
- Primary Topic
- Laser-Matter Interactions and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China
- Program of Shanghai Academic Research Leader