AffiliationUniv Arizona, Coll Opt Sci
MetadataShow full item record
PublisherAMER PHYSICAL SOC
CitationOptical gain in rotationally excited nitrogen molecular ions 2017, 96 (5) Physical Review A
JournalPhysical Review A
Rights© 2017 American Physical Society.
Collection InformationThis 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 firstname.lastname@example.org.
AbstractWe 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.
VersionFinal published version
SponsorsU.S. Air Force Office of Scientific Research under MURI Award [FA9550-16-1-0013]