Abstract
Spectroscopic gas sensing and its applications to, for example, trace detection or chemical kinetics, require ever more demanding measurement times, acquisition rates, sensitivities, precisions and broad tuning ranges. Here, we propose a new approach to near-infrared molecular spectroscopy, utilizing advanced concepts of optical telecommunications and supercontinuum photonics. We generate, without mode-locked lasers, two frequency combs of slightly different repetition frequencies and moderate, but rapidly tunable, spectral span. The output of a frequency-agile continuous-wave laser is split and sent into two electro-optic intensity modulators. Flat-top low-noise frequency combs are produced by wave-breaking in a nonlinear optical fibre of normal dispersion. With a dual-comb spectrometer, we record Doppler-limited spectra spanning 60 GHz within 13 mu s and an 80 kHz refresh rate, at a tuning speed of 10 nm s(-1). The sensitivity for weak absorption is enhanced by a long gas-filled hollow-core fibre. New opportunities for real-time diagnostics may be opened up, even outside the laboratory.
Item Type: | Journal article |
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Faculties: | Physics |
Subjects: | 500 Science > 530 Physics |
ISSN: | 1749-4885 |
Language: | English |
Item ID: | 47753 |
Date Deposited: | 27. Apr 2018, 08:13 |
Last Modified: | 04. Nov 2020, 13:24 |