Cascaded amplification of air lasing.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41004594.
- Also identified by DOI 10.1126/sciadv.ady7458 and PMC identifier 12467049.
- Licence recorded as CC BY-NC.
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Abstract
Air lasing initiated by femtosecond laser filamentation holds exciting prospects for remote sensing. However, low output energies restrict its practical applications. We demonstrate a cascaded amplification strategy that breaks this critical barrier. By implementing quadruple-pass focusing of 5.7-millijoule, 800-nanometer femtosecond pulses in nitrogen, we achieve a 40-fold enhancement in the energy of [Formula: see text] lasing, yielding an output of approximately 4.4 microjoules. This multipass configuration also reduces the lasing threshold by nearly 70%, facilitates spectral broadening of pump pulses, and compresses the pulse duration of [Formula: see text] lasing. Capitalizing on these combined effects, we developed a single-beam coherent Raman spectroscopy, which enables simultaneous detection of multiple species and exhibits high sensitivity at the parts-per-million level. This work successfully addresses the energy bottleneck of air lasing using only commercially available femtosecond lasers and provides a promising approach for standoff chemical analysis.