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PhysRevA.96.051401.pdf
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Final Published Version
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AMER PHYSICAL SOCCitation
Optical gain in rotationally excited nitrogen molecular ions 2017, 96 (5) Physical Review AJournal
Physical Review ARights
© 2017 American Physical Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We pump low-pressure nitrogen gas with ionizing femtosecond laser pulses at 1.5 mu m wavelength. The resulting rotationally excited N-2(+) 2 molecular ions generate directional, forward-propagating stimulated and isotropic spontaneous emissions at 428 nmwavelength. Through high-resolution spectroscopy of these emissions, we quantify rotational population distributions in the upper and lower emission levels. We show that these distributions are shifted with respect to each other, which has a strong influence on the transient optical gain in this system. Although we find that electronic population inversion exists in our particular experiment, we show that sufficient dissimilarity of rotational distributions in the upper and lower emission levels could, in principle, lead to gain without net electronic population inversion.ISSN
2469-99262469-9934
Version
Final published versionSponsors
U.S. Air Force Office of Scientific Research under MURI Award [FA9550-16-1-0013]Additional Links
https://link.aps.org/doi/10.1103/PhysRevA.96.051401ae974a485f413a2113503eed53cd6c53
10.1103/PhysRevA.96.051401