Quantitative modeling of complex molecular response in coherent cavity-enhanced dual-comb spectroscopy

Fleisher, Adam J.; Long, David A.; Hodges, Joseph T.

doi:10.1016/j.jms.2018.07.010

Cited by 14 publications

(5 citation statements)

References 95 publications

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“…CBDS achieves high accuracy through precise measurement of the cavity resonance frequencies, and accurate modeling and fitting of the buildup signals in the frequency domain. The generality of our field-based method enables applications to dynamic cavity-enhanced sensing throughout the electromagnetic spectrum, making the method amenable to the analysis of intermode 24 and multiplexed 25 buildup signals with detuned local excitation fields. When dynamic events are not of interest, the tightly locked optical scheme allows for coherent timedomain averaging of CBDS signals, and therefore ultrahigh precision with minimal data storage and no dead time.…”

Section: (B)mentioning

confidence: 99%

Cavity buildup dispersion spectroscopy

et al. 2021

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Measurements of ultrahigh-fidelity absorption spectra can help validate quantum theory, engineer ultracold chemistry, and remotely sense atmospheres. Recent achievements in cavity-enhanced spectroscopy using either frequency-based dispersion or time-based absorption approaches have set new records for accuracy with uncertainties at the sub-per-mil level. However, laser scanning or susceptibility to nonlinearities limits their ultimate performance. Here we present cavity buildup dispersion spectroscopy (CBDS), probing the CO molecule as an example, in which the dispersive frequency shift of a cavity resonance is encoded in the cavity’s transient response to a phase-locked non-resonant laser excitation. Beating between optical frequencies during buildup exactly localizes detuning from mode center, and thus enables single-shot dispersion measurements. CBDS can yield an accuracy limited by the chosen frequency standard and measurement duration and is currently 50 times less susceptible to detection nonlinearity compared to intensity-based methods. Moreover, CBDS is significantly faster than previous frequency-based cavity-enhanced methods. The generality of CBDS shows promise for improving fundamental research into a variety of light–matter interactions.

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Section: (B)mentioning

confidence: 99%

Cavity buildup dispersion spectroscopy

et al. 2021

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“…The additional strong resonances in Fig. 2 d correspond to beating between the probe comb steady-state cavity transmission and the local oscillator comb—signals which are used in conventional dual-comb spectroscopy 15 , 22 , 28 , but which are not used in the present analysis.…”

Section: Resultsmentioning

confidence: 99%

“…Alternatively, Fourier transform cavity-enhanced spectroscopy has been demonstrated using either dual-comb interferometry [13,14,15,16] or with a mechanically scanned spectrometer [17,18,19]. Importantly, these techniques are susceptible to cavity dispersion which causes a mismatch between the probe comb and the comb-like grid of cavity resonances [20,21].…”

Section: Introductionmentioning

confidence: 99%

Dual-comb cavity ring-down spectroscopy

Lisak

Charczun

Nishiyama

et al. 2022

Sci Rep

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Cavity ring-down spectroscopy is a ubiquitous optical method used to study light-matter interactions with high resolution, sensitivity and accuracy. However, it has never been performed with the multiplexing advantages of direct frequency comb spectroscopy without significantly compromising spectral resolution. We present dual-comb cavity ring-down spectroscopy (DC-CRDS) based on the parallel heterodyne detection of ring-down signals with a local oscillator comb to yield absorption and dispersion spectra. These spectra are obtained from widths and positions of cavity modes. We present two approaches which leverage the dynamic cavity response to coherently or randomly driven changes in the amplitude or frequency of the probe field. Both techniques yield accurate spectra of methane—an important greenhouse gas and breath biomarker. When combined with broadband frequency combs, the high sensitivity, spectral resolution and accuracy of our DC-CRDS technique shows promise for applications like studies of the structure and dynamics of large molecules, multispecies trace gas detection and isotopic composition.

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“…The transmission spectrum is the distribution of cavity modes at on- and off-axis excitation, as shown in Figure a,b. Due to the objective existence of intracavity dispersion, this frequency interval can be described by the frequency-dependent free spectral range (FSR) as follows: FSR ( ω 0 ) = c 2 n L C + δϕ ( ω 0 ) δω where c represents the speed of light in vacuum, n represents the refractive index of the gas in the cavity, usually taken as 1, L C is the cavity length, and δφ(ω 0 )/δω represents the total dispersion in the cavity, including that of the mirrors and the gas molecules to be analyzed . Compared with the round-trip phase shift δφ(ω) = 2ω L C / c for the optical field propagation in the dispersion-free cavity, the intracavity total dispersion brings an additional phase shift ϕ(ω).…”

Section: Principles and Theoretical Simulationsmentioning

confidence: 99%

“…where c represents the speed of light in vacuum, n represents the refractive index of the gas in the cavity, usually taken as 1, L C is the cavity length, and δφ(ω 0 )/δω represents the total dispersion in the cavity, including that of the mirrors and the gas molecules to be analyzed. 23 Compared with the round-trip phase shift δφ(ω) = 2ωL C /c for the optical field propagation in the dispersion-free cavity, the intracavity total dispersion brings an additional phase shift ϕ(ω).…”

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confidence: 99%

Near-Infrared Off-Axis Cavity-Enhanced Optical Frequency Comb Spectroscopy for CO₂/CO Dual-Gas Detection Assisted by Machine Learning

Guan,

Liu,

et al. 2024

ACS Sens.

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Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) is widely used as a highly sensitive gas sensing technology in various gas detection fields. For the on-axis coupling incidence scheme, the detection accuracy and stability are seriously affected by the cavity-mode noise, and therefore, stable operation inevitably requires external electronic mode-locking and sweeping devices, substantially increasing system complexity. To address this issue, we propose off-axis cavity-enhanced optical frequency comb spectroscopy from both theoretical and experimental aspects, which is applied to the detection of single-and dualgas of carbon monoxide (CO) and carbon dioxide (CO 2 ) in the near-infrared. An erbium-doped fiber frequency comb with a repetition frequency of ∼41.709 MHz is coupled into a resonant cavity with a length of ∼360 mm in an off-axis manner, exciting numerous high-order modes to effectively suppress cavity-mode noise. The performance of multiple machine learning models is compared for the inversion of a single/dual gas concentration. A few absorbance spectra are collected to build a sample data set, which is then utilized for model training and learning. The results demonstrate that the Particle Swarm Optimization Support Vector Machine (PSO-SVM) model achieves the highest predictive accuracy for gas concentration and is ultimately applied to the detection system. Based on Allan deviation, the detection limit for CO in single-gas detection can reach 8.247 parts per million by volume (ppmv) by averaging 87 spectra. Meanwhile, for simultaneous CO 2 /CO measurement with highly overlapping absorbance spectra, the LoD can be reduced to 13.196 and 4.658 ppmv, respectively. The proposed optical gas sensing technique indicates the potential for the development of a field-deployable and intelligent sensor system capable of simultaneous detection of multiple gases.

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Quantitative modeling of complex molecular response in coherent cavity-enhanced dual-comb spectroscopy

Cited by 14 publications

References 95 publications

Cavity buildup dispersion spectroscopy

Cavity buildup dispersion spectroscopy

Dual-comb cavity ring-down spectroscopy

Near-Infrared Off-Axis Cavity-Enhanced Optical Frequency Comb Spectroscopy for CO₂/CO Dual-Gas Detection Assisted by Machine Learning

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Quantitative modeling of complex molecular response in coherent cavity-enhanced dual-comb spectroscopy

Cited by 14 publications

References 95 publications

Cavity buildup dispersion spectroscopy

Cavity buildup dispersion spectroscopy

Dual-comb cavity ring-down spectroscopy

Near-Infrared Off-Axis Cavity-Enhanced Optical Frequency Comb Spectroscopy for CO2/CO Dual-Gas Detection Assisted by Machine Learning

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Near-Infrared Off-Axis Cavity-Enhanced Optical Frequency Comb Spectroscopy for CO₂/CO Dual-Gas Detection Assisted by Machine Learning