Jan, 2018
Vibrational excitation of hydrogen molecules by two-photon absorption and third-harmonic generation
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
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- Volume
- 51
- Number
- 1
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1088/1361-6455/aa9782
- Publisher
- IOP PUBLISHING LTD
We report the coherent excitation of the vibrational state of hydrogen molecules by two-photon absorption and the resultant third-harmonic generation (THG). Parahydrogen molecules cooled by liquid nitrogen are irradiated by mid-infrared nanosecond pulses at 4.8 mu m with a nearly Fourier-transform-limited linewidth. The first excited vibrational state of parahydrogen is populated by two-photon absorption of the mid-infrared photons. Because of the narrow linewidth of the mid-infrared pulses, coherence between the ground and excited states is sufficient to induce higher-order processes. Near-infrared photons from the THG are observed at 1.6 mu m. The dependence of the intensity of the near-infrared radiation on mid-infrared pulse energy, target pressure, and cell length is determined. We used a simple formula for THG with consideration of realistic experimental conditions to explain the observed results.
- Link information
- ID information
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- DOI : 10.1088/1361-6455/aa9782
- ISSN : 0953-4075
- eISSN : 1361-6455
- Web of Science ID : WOS:000417515900001