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arXiv · 1405.6528

Gain dynamics of a free-space nitrogen laser pumped by circularly polarized femtosecond laser pulses

Jinping Yao·Hongqiang Xie·Bin Zeng·Wei Chu·Guihua Li·Jielei Ni·Haisu Zhang·Chenrui Jing·Chaojin Zhang·Huailiang Xu·Ya Cheng·Zhizhan Xu
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Abstract

We experimentally demonstrate ultrafast dynamic of generation of a strong 337-nm nitrogen laser by injecting an external seed pulse into a femtosecond laser filament pumped by a circularly polarized laser pulse. In the pump-probe scheme, it is revealed that the population inversion between the excited and ground states of N2 for the free-space 337-nm laser is firstly built up on the timescale of several picoseconds, followed by a relatively slow decay on the timescale of tens of picoseconds, depending on the nitrogen gas pressure. By measuring the intensities of 337-nm signal from nitrogen gas mixed with different concentrations of oxygen gas, it is also found that oxygen molecules have a significant quenching effect on the nitrogen laser signal. Our experimental observations agree with the picture of electron-impact excitation.

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Jinping Yao, Hongqiang Xie, Bin Zeng, Wei Chu, Guihua Li, Jielei Ni, Haisu Zhang, Chenrui Jing, Chaojin Zhang, Huailiang Xu, Ya Cheng, Zhizhan Xu. 2014-05-26. Gain dynamics of a free-space nitrogen laser pumped by circularly polarized femtosecond laser pulses. https://doi.org/10.1364/oe.22.019005

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