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| Main Authors: | , |
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| Format: | Preprint |
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2026
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| Online Access: | https://arxiv.org/abs/2604.26512 |
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| _version_ | 1866915967466995712 |
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| author | Luo, Pei-Ling Chen, I-Yun |
| author_facet | Luo, Pei-Ling Chen, I-Yun |
| contents | Dual-comb spectroscopy enables broadband, high-resolution measurements with microsecond temporal resolution, but extending this capability to the 10~12.5 $μ$m molecular fingerprint region remains technically challenging, particularly for transient radical kinetics. Here, we demonstrate microsecond-resolved dual-comb spectroscopy in this spectral range using electro-optic combs and difference-frequency generation in an orientation-patterned gallium phosphide crystal. Operation near a turning-point quasi-phase-matching condition at approximately 140 $^\circ$C reduces the wavelength sensitivity of the nonlinear conversion, enabling robust tuning of the idler comb over 83 cm$^{-1}$, corresponding to approximately 1.2 $μ$m near 12 $μ$m, by adjusting only the signal-comb center wavelength while keeping the pump wavelength and crystal temperature fixed. As a demonstration, we perform high-resolution, microsecond-resolved spectroscopy of transient chlorine monoxide (ClO) near 12 $μ$m. Time-resolved dual-comb spectra capture the temporal evolution of ClO produced by the Cl + O$_3$ reaction with a temporal resolution of 1.5 $μ$s, enabling quantitative determination of the ClO formation rate coefficient. These results establish this dual-comb platform as a promising tool for quantitative, microsecond-resolved studies of short-lived radicals, particularly atmospherically relevant halogen oxides. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_26512 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Microsecond-resolved electro-optic dual-comb spectroscopy in the 10~12.5 $μ$m fingerprint region for radical kinetics Luo, Pei-Ling Chen, I-Yun Optics Chemical Physics Dual-comb spectroscopy enables broadband, high-resolution measurements with microsecond temporal resolution, but extending this capability to the 10~12.5 $μ$m molecular fingerprint region remains technically challenging, particularly for transient radical kinetics. Here, we demonstrate microsecond-resolved dual-comb spectroscopy in this spectral range using electro-optic combs and difference-frequency generation in an orientation-patterned gallium phosphide crystal. Operation near a turning-point quasi-phase-matching condition at approximately 140 $^\circ$C reduces the wavelength sensitivity of the nonlinear conversion, enabling robust tuning of the idler comb over 83 cm$^{-1}$, corresponding to approximately 1.2 $μ$m near 12 $μ$m, by adjusting only the signal-comb center wavelength while keeping the pump wavelength and crystal temperature fixed. As a demonstration, we perform high-resolution, microsecond-resolved spectroscopy of transient chlorine monoxide (ClO) near 12 $μ$m. Time-resolved dual-comb spectra capture the temporal evolution of ClO produced by the Cl + O$_3$ reaction with a temporal resolution of 1.5 $μ$s, enabling quantitative determination of the ClO formation rate coefficient. These results establish this dual-comb platform as a promising tool for quantitative, microsecond-resolved studies of short-lived radicals, particularly atmospherically relevant halogen oxides. |
| title | Microsecond-resolved electro-optic dual-comb spectroscopy in the 10~12.5 $μ$m fingerprint region for radical kinetics |
| topic | Optics Chemical Physics |
| url | https://arxiv.org/abs/2604.26512 |