New paper: improved Vernier spectrometer with our compact frequency comb

We presented a new design of a Vernier spectrometer for broadband, fast and sensitive detection of carbon dioxide and methane. The spectrometer uses our compact fiber-based frequency comb. The research was done in collaboration with the group of Dr. Aleksandra Foltynowicz from Umea University. The paper was published in Optics Express.

We demonstrated a new, improved design of a continuous-filtering Vernier spectrometer based on a compact fs Er-doped fiber laser and a rotating aperture that selects one Vernier order. The simplified and more robust spectrometer acquires spectra with similar resolution as in previous demonstrations of the technique (a few GHz), but at 5 times faster rates (up to 100 Hz). The spectrometer allows recording the entire emission spectrum of the femtosecond laser in one scan, and we demonstrated its operation around two center wavelengths – 1575 nm and 1650 nm, where the latter is demonstrated for the first time using this technique. We recorded spectra of CO2 covering 1.7 THz of bandwidth at 1575 nm, and of CH4, covering 2.7 THz at 1650 nm. The demonstrated absorption sensitivity is comparable to that of other robust cavity-enhanced techniques, e.g. off-axis integrated cavity output spectroscopy, while the spectral bandwidth is significantly increased. The free-running capability of the spectrometer combined with the compactness of the laser source represents a significant step towards robust cavity-enhanced optical frequency comb spectroscopy, which can lead to field-deployable cavity-enhanced instruments.

The paper is available online (Open Access):

https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-29-19-30155

Source: Chuang Lu, Francisco Senna Vieira, Aleksander Głuszek, Isak Silander, Grzegorz Soboń, and Aleksandra Foltynowicz, "Robust, fast and sensitive near-infrared continuous-filtering Vernier spectrometer," Opt. Express 29, 30155-30167 (2021)

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