Saturated absorption spectroscopy of buffer-gas-cooled Barium monofluoride molecules

• Published in: arXiv.org
• Main Authors: Bu, Wenhao, Zhang, Yuhe, Liang, Qian, Chen, Tao, Yan, Bo
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 13.02.2023
• Subjects: Absorption spectroscopy; Barium; Buffers; Laser cooling; Physics - Atomic Physics; Physics - Chemical Physics; Spectrum analysis
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2202.02463

We report an experimental investigation on the Doppler-free saturated absorption spectroscopy of buffer-gas-cooled Barium monofluoride (BaF) molecules in a 4~K cryogenic cell. The obtained spectra with a resolution of 19~MHz, much smaller than previously observed in absorption spectroscopy, clearly resolve the hyperfine transitions. Moreover, we use these high-resolution spectra to fit the hyperfine splittings of excited \(A(v=0)\) state and find the hyperfine splitting of the laser-cooling-relevant \(A^2\Pi_{1/2}(v=0, J=1/2, +)\) state is about 18 MHz, much higher than the previous theoretically predicted value. This provides important missing information for laser cooling of BaF molecules.