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arXiv · 1910.13596

Extreme nonlinear Raman interaction of an ultrashort nitrogen ion laser with an impulsively excited molecular wavepacket

Zhaoxiang Liu·Jinping Yao·Haisu Zhang·Bo Xu·Jinming Chen·Fangbo Zhang·Zhihao Zhang·Yuexin Wan·Wei Chu·Zhenhua Wang·Ya Cheng
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Abstract

We report generation of cascaded rotational Raman scattering up to 58th orders in coherently excited CO_2 molecules. The high-order Raman scattering, which produces a quasiperiodic frequency comb with more than 600 sidebands, is obtained using an intense femtosecond laser to impulsively excite rotational coherence and the femtosecond-laser-induced N_2^+ lasing to generate cascaded Raman signals. The novel configuration allows this experiment to be performed with a single femtosecond laser beam at free-space standoff locations. It is revealed that the efficient spectral extension of Raman signals is attributed to the specific spectra-temporal structures of N_2^+ lasing, the ideal spatial overlap of femtosecond laser and N2+ lasing, and the guiding effect of molecular alignment. The Raman spectrum extending above 2000 cm^-1 naturally corresponds to a femtosecond pulse train due to the periodic revivals of molecular rotational wavepackets.

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Zhaoxiang Liu, Jinping Yao, Haisu Zhang, Bo Xu, Jinming Chen, Fangbo Zhang, Zhihao Zhang, Yuexin Wan, Wei Chu, Zhenhua Wang, Ya Cheng. 2019-10-30. Extreme nonlinear Raman interaction of an ultrashort nitrogen ion laser with an impulsively excited molecular wavepacket. https://doi.org/10.1103/physreva.101.043404

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