Optics Express

Vibrational Raman scattering from coherently excited molecular ions in a strong laser field

Bo Xu, Jinping Yao, Yuexin Wan, Jinming Chen, Zhaoxiang Liu, Fangbo Zhang, Wei Chu, Ya Cheng

Published Jun 14, 2019• 11 citations

Abstract

We report on a pump-probe investigation of vibrational Raman scattering from coherently excited N2+ ions. It is found that the Raman signals produced by the inelastic scattering of the probe pulse from molecular ions can be dramatically enhanced when the probe laser is resonant with electronic transitions in N2+ ions. The Raman signal can be amplified at 428 nm wavelength due to the presence of population inversion in N2+ ions.

DOI: 10.1364/oe.27.018262

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Optics Express

Vibrational Raman scattering from coherently excited molecular ions in a strong laser field

Bo Xu, Jinping Yao, Yuexin Wan, Jinming Chen, Zhaoxiang Liu, Fangbo Zhang, Wei Chu, Ya Cheng

Published Jun 14, 2019• 11 citations

Publisher

Abstract

DOI: 10.1364/oe.27.018262

Related papers

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We report a combined theoretical and experimental investigation on the unambiguous role of electronic coherence underlying the generation of laserlike coherent emission from

{{\mathrm{N}}_{2}}^{+}

ions launched in a strong laser field. The coherence manifests itself by giving rise to a dramatic enhancement of

{{\mathrm{N}}_{2}}^{+}

laserlike radiation with two temporally separated pump laser pulses centered at 800- and 1580-nm wavelengths, respectively. We further show that coherent control of

{{\mathrm{N}}_{2}}^{+}

lasing in a subfemtosecond timescale can be achieved by replacing the single 800-nm laser pulse with a pair of 800-nm laser pulses of adjustable time delay. The experimental results are well reproduced in theory using a three-level quantum model of

{{\mathrm{N}}_{2}}^{+}

ions under the density matrix representation.

We report on the generation of cascaded rotational Raman scattering up to 58th order in coherently excited

\mathrm{C}{\mathrm{O}}_{2}

molecules. Raman scattering with more than 600 sidebands is obtained using an intense femtosecond laser to impulsively excite rotational coherence and femtosecond-laser-induced

{{\mathrm{N}}_{2}}^{+}

lasing to generate cascaded Raman signals. This 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 structures of

{{\mathrm{N}}_{2}}^{+}

lasing in the spectral and temporal domains and the ideal spatial overlap of the femtosecond laser and

{{\mathrm{N}}_{2}}^{+}

lasing. A Raman spectrum extending above $2000\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$ naturally corresponds to a femtosecond pulse train due to the periodic revivals of molecular rotational wave packets.