Mid infrared gas spectroscopy using efficient fiber laser driven photonic chip-based supercontinuum.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30948726.
- Also identified by DOI 10.1038/s41467-019-09590-3 and PMC identifier 6449389.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Directly accessing the middle infrared, the molecular functional group spectral region, via supercontinuum generation processes based on turn-key fiber lasers offers the undeniable advantage of simplicity and robustness. Recently, the assessment of the coherence of the mid-IR dispersive wave in silicon nitride (Si<sub>3</sub>N<sub>4</sub>) waveguides, pumped at telecom wavelength, established an important first step towards mid-IR frequency comb generation based on such compact systems. Yet, the spectral reach and efficiency still fall short for practical implementation. Here, we experimentally demonstrate that large cross-section Si<sub>3</sub>N<sub>4</sub> waveguides pumped with 2 μm fs-fiber laser can reach the important spectroscopic spectral region in the 3-4 μm range, with up to 35% power conversion and milliwatt-level output powers. As a proof of principle, we use this source for detection of C<sub>2</sub>H<sub>2</sub> by absorption spectroscopy. Such result makes these sources suitable candidate for compact, chip-integrated spectroscopic and sensing applications.