Enhanced spectral resolution in mid-infrared dual-comb spectroscopy via synchronous offset frequency tuning DOI Creative Commons
Bocheng Tang,

Zhong Zhou Yi,

Qingzhao Yang

et al.

Optics Express, Journal Year: 2024, Volume and Issue: 33(1), P. 910 - 910

Published: Dec. 19, 2024

Mid-infrared dual-comb spectroscopy offers significant advantages by combining the high sensitivity of mid-infrared with spectral resolution and rapid acquisition method. However, its effective resolution, constrained inherent comb line spacing, hinders ability to resolve narrow absorption features, common in critical applications such as sub-Doppler spectroscopy, low-pressure gas analysis, construction atmospheric profile. To address this challenge, we present a synchronous offset frequency tuning method for system improve far beyond spacing. In our system, source is generated from near-infrared continuous-wave pump laser via difference generation single periodically poled lithium niobate bulk. By adjusting phase-lock one combs, synchronously tune frequencies both combs without changing source. We demonstrated that enabled overlapped lines ethane around 3000 cm-1, achieving uniform sampling interval 10 MHz interleaved spectrum 25-fold enhancement resolution. This approach allows sub-MHz any modifications data offering possibilities high-precision analysis.

Language: Английский

Real-Time Measurement of CH4 in Human Breath Using a Compact CH4/CO2 Sensor DOI Creative Commons
Yueyu Lin,

Dexter Manalili,

Amir Khodabakhsh

et al.

Sensors, Journal Year: 2024, Volume and Issue: 24(4), P. 1077 - 1077

Published: Feb. 7, 2024

The presence of an elevated amount methane (CH4) in exhaled breath can be used as a non-invasive tool to monitor certain health conditions. A compact, inexpensive and transportable CH4 sensor is thus very interesting for this purpose. In addition, if the also able simultaneously measure carbon dioxide (CO2), one extract end-tidal concentration CH4. Here, we report on such based commercial detection module using tunable diode laser absorption spectroscopy. It was found that measured CH4/CO2 values exhibit strong interference with water vapor. Therefore, correction functions were experimentally identified validated both CO2 custom-built sampler developed tested real-time measurements breath. As result, demonstrated capability accurately measuring profiles real-time. We obtained minimum limits ~80 ppbv ~700 ppmv 1.5 s measurement time.

Language: Английский

Citations

5
Phase Noise Characterization of Cr:ZnS Frequency Comb using Subspace Tracking DOI
Aleksandr Razumov, Sergey Vasilyev, Mike Mirov

et al.

Optics Letters, Journal Year: 2025, Volume and Issue: 50(6), P. 1873 - 1873

Published: Feb. 12, 2025

We present a comprehensive phase noise characterization of mid-IR Cr:ZnS frequency comb. Despite their emergence as platform for high-resolution dual-comb spectroscopy (DCS), detailed investigations into the combs have been lacking. To address this, we use recently proposed measurement technique that employs multi-heterodyne detection and subspace tracking. This allows common mode, repetition rate, high-order terms corresponding scaling function comb-line number, using single setup. demonstrate comb under test is dominated by mode noise, while all other are below floor (∼-120 dB rad2/Hz) thereby not identifiable.

Language: Английский

Citations

0
Ultra-Broadband Coherent Open-Path Spectroscopy for Multi-Gas Monitoring in Wastewater Treatment DOI Creative Commons
R. Krebbers, K. van Kempen, Yueyu Lin

et al.

Environmental Science and Ecotechnology, Journal Year: 2025, Volume and Issue: unknown, P. 100554 - 100554

Published: March 1, 2025

Wastewater treatment plants significantly contribute to greenhouse gas emissions, including nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4). Current methods measure these emissions typically target specific molecular compounds, providing limited scope potentially incomplete profiles. Here, we show an innovative ultra-broadband coherent open-path spectroscopy (COPS) system capable of simultaneously monitoring multiple gases. This novel approach combines Fourier transform with a coherent, mid-infrared light source spanning 2-11.5 μm at approximately 3 W power. Positioned above aeration tank, the COPS selectively detected absorption signatures for CH4, CO2, N2O, ammonia (NH3), monoxide (CO), water vapor (H2O), enabling real-time, path-integrated concentration measurements temporal resolution 40 s. Elevated concentrations CH4 CO2 were clearly identified within emission plumes traversing beam path tank. Additionally, patterns closely tracked variations in ammonium loading from incoming wastewater, whereas correlated strongly oxygen introduced during aeration. Measurements NH3, CO stable aligned traditional point-based commercial analyzers. Our findings demonstrate that offers robust, comprehensive solution simultaneous real-time gases complex heterogeneous environments. capability enhances atmospheric industrial assessments, transforming quantification environmental management.

Language: Английский

Citations

0
All-mirror wavefront division interferometer for Fourier-transform spectrometry across multiple spectral ranges DOI Creative Commons
Ivan Zorin, Paul Gattinger, Giovanna Ricchiuti

et al.

Optics Express, Journal Year: 2024, Volume and Issue: 33(1), P. 867 - 867

Published: Dec. 6, 2024

We report on the design of an all-mirror wavefront-division interferometer capable spectroscopic studies across multiple spectral ranges-from plasma frequencies metals to terahertz wavelengths and beyond. The proposed method leverages properties laser sources with high spatial coherence. A theoretical framework for scheme is presented, along analytical solution determining far-field interference pattern, which validated through both optical propagation simulations experimental results. practical implementation spectrometer, using cost-effective off-the-shelf components (knife-edge prisms separation recombination), demonstrated. system features ultra-broad bandwidth, throughput, simple architecture, dispersion-free operation, variable arm split ratio. These unique attributes make our approach a prospective alternative standard Fourier transform spectrometer schemes, specifically tailored laser-based scenarios. Further, employed inherently enables measurement sample's dispersion. In section, we demonstrate feasibility measurements by coupling supercontinuum source more than octave-spanning range (1.5 µm - 4.4 µm). As proof-of-concept, demonstration provided various applied studies: transmission polymers (polypropylene) gas (methane), as well reflectance dried pharmaceuticals (insulin products metal surface).

Language: Английский

Citations

0
In-situ analysis of methane plasmas with mid-infrared supercontinuum-based Fourier-transform spectroscopy DOI Creative Commons
R. Krebbers, Ningwu Liu,

Wessel Averink

et al.

Applied Physics B, Journal Year: 2024, Volume and Issue: 131(1)

Published: Dec. 10, 2024

The conversion of methane (CH4) into the hydrocarbons ethane (C2H6) and acetylene (C2H2) in plasma is investigated first in-situ study using a mid-infrared supercontinuum source Fourier transform spectrometer. Due to spatial coherence source, it possible probe over path length 3.5 m observe CH4, C2H6, C2H2 with concentrations below percent level at few mbar pressure. broad spectral range (1.4–4.1 μm) covers entire rovibrational bands molecules, allowing simultaneous detection rotational vibrational temperature CH4 C2H2. ability these experimental parameters situ opens new possibilities for understanding optimizing plasma-based chemical conversions.

Language: Английский

Citations

0
Enhanced spectral resolution in mid-infrared dual-comb spectroscopy via synchronous offset frequency tuning DOI Creative Commons
Bocheng Tang,

Zhong Zhou Yi,

Qingzhao Yang

et al.

Optics Express, Journal Year: 2024, Volume and Issue: 33(1), P. 910 - 910

Published: Dec. 19, 2024

Mid-infrared dual-comb spectroscopy offers significant advantages by combining the high sensitivity of mid-infrared with spectral resolution and rapid acquisition method. However, its effective resolution, constrained inherent comb line spacing, hinders ability to resolve narrow absorption features, common in critical applications such as sub-Doppler spectroscopy, low-pressure gas analysis, construction atmospheric profile. To address this challenge, we present a synchronous offset frequency tuning method for system improve far beyond spacing. In our system, source is generated from near-infrared continuous-wave pump laser via difference generation single periodically poled lithium niobate bulk. By adjusting phase-lock one combs, synchronously tune frequencies both combs without changing source. We demonstrated that enabled overlapped lines ethane around 3000 cm-1, achieving uniform sampling interval 10 MHz interleaved spectrum 25-fold enhancement resolution. This approach allows sub-MHz any modifications data offering possibilities high-precision analysis.

Language: Английский

Citations

0