Open AccessOptical amplification from high vibrational states of ionized nitrogen molecules generated by 800-nm femtosecond laser pulses
Author(s) -
Zhiming Miao,
Zheng Wei,
Weijia Yang,
Chao Dai,
Zheng Li,
Chengyin Wu
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.414843
Subject(s) - laser , femtosecond , materials science , atomic physics , ionization , ion , optics , laser pumping , population , polarization (electrochemistry) , physics , chemistry , demography , quantum mechanics , sociology
We experimentally investigated the interaction between nitrogen molecules and intense femtosecond laser pulses. When irradiated by an 800-nm pump laser and a delayed 355-nm seed laser, the spectral lines around 353.3 nm and 353.8 nm are observed to be greatly amplified, no matter whether the pump laser is circularly or linearly polarized. The two spectral lines correspond to the transition of N 2 + (B, ν' = 5 → X, ν = 4) and N 2 + (B, ν' = 4 → X, ν = 3), respectively. In comparison with the spectral lines related with ground vibrational states of nitrogen molecular ion, the observed amplification exhibits different polarization dependence of the pump laser. This distinctive change can be explained by the population variation of high vibrational states caused by the pump laser with different polarizations.