Article
Optics
Erin M. Adkins, David A. Long, Adam J. Fleisher, Joseph T. Hodges
Summary: Using frequency-agile rapid scanning cavity ring-down spectroscopy, the line intensities and line shape parameters of N-14(2) O-16 in air near 1.6 μm were measured and modeled with multi-spectrum fits of Voigt and speed-dependent Voigt profiles. Deviations of several percent relative to values in HITRAN 2016 were found, with measured intensities having relative combined standard uncertainties of approximately 1%, which is five times smaller than literature values. Comparison with experimental literature values for other rotation-vibration bands of N2O showed significant differences in magnitude and J-dependence, suggesting that the assumption of band-independent line shape parameters is not appropriate for applications requiring high spectral fidelity.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2021)
Article
Environmental Sciences
Ian J. Brown, Vassilis Kitidis, Andrew P. Rees
Summary: The development of an automated system using commercially available CRDS technology allows for the equilibration and analysis of dissolved N2O and CH4 in seawater. This system was successfully deployed during two research cruises in the Atlantic Ocean, covering a total distance of 16,500 km. The CRDS measurements showed excellent agreement with discretely collected samples analyzed using GC, providing higher analytical precision and greatly increasing the available data on dissolved N2O and CH4.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Instruments & Instrumentation
Soumyadipta Chakraborty, Ardhendu Pal, Biswajit Panda, Indrayani Patra, Manik Pradhan
Summary: High-sensitive CRDS coupled with a cw-quantum cascade laser has been used to investigate the rovibrational interaction coupling for various rotational transitions of β-N2O in the MIR region. The rotational interaction was quantified from the CRDS data and a data-driven approach was taken for the approximation of the Herman-Wallis series. The study reveals the fundamental infrared physics underlying the rovibrational interaction and its coupling to the vibrational and rotational degrees of freedom for β-N2O.
INFRARED PHYSICS & TECHNOLOGY
(2023)
Article
Chemistry, Analytical
Coralie Elmaleh, Fabien Simon, Jean Decker, Julien Dumont, Fabrice Cazier, Marc Fourmentin, Robin Bocquet, Arnaud Cuisset, Gael Mouret, Francis Hindle
Summary: The development of cavity based infrared spectroscopy techniques, particularly cavity ring-down spectroscopy, has been successful for sensitive measurements. However, the construction difficulty of high finesse cavities has limited its application for THz frequencies. By using a corrugated waveguide and photonic mirrors, we have achieved finesse values of 3500. This has allowed us to measure the absorption of various gases and samples, demonstrating good agreement with a certified gas analyser for industrial samples.
Article
Optics
Min Yang, Zhen Wang, Qinxue Nie, Kai Ni, Wei Ren
Summary: The study presents a mid-infrared gas sensor for detecting atmospheric N2O using DFB-QCL and F-P optical cavity, achieving a low detection limit and absorption spectral measurement of ambient air. This provides a promising approach for developing compact and sensitive gas sensors for environmental monitoring.
Article
Physics, Atomic, Molecular & Chemical
Ardhendu Pal, Biswajit Panda, Sanchi Maithani, Manik Pradhan
Summary: The study investigates the spectroscopic features of the l-type doublets of site-specific 15N isotopomers of nitrous oxide, determining new spectroscopic parameters and analyzing the effects of temperature, pressure, and pressure broadening coefficients. The research provides insights into the molecular properties of the 15N isotopes of N2O and their distribution within the isotopomers.
JOURNAL OF MOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Analytical
Anuj Chauhan, Namasivayam Dhenadhayalan, King-Chuen Lin
Summary: The use of EW-CRDS technology as a highly sensitive and efficient sensing technique for the detection of PSA with sub-femtomolar LOD was successful. Gold nanoparticles as sensitive reporters exhibited strong adsorption kinetics and promising applications in biological detection.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Construction & Building Technology
Daire E. Browne, Robert Peverall, Grant A. D. Ritchie, Heather A. Viles
Summary: Enhanced understanding of drying kinetics of building materials is important for durability explanation and conservation improvement. Cavity ring-down spectroscopy is demonstrated as an effective method to investigate drying kinetics, and it is applied here to study the drying behavior of commonly used building limestones and sandstone. The time for phase I drying increases with porosity, but the constant mass flux remains unchanged. Phase II drying diffusivities vary for different materials and are not solely controlled by porosity. Activation energies associated with phase II drying are determined for specific materials.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Optics
Neus A. Calvet, Wolfgang Paa, Benjamin Dietzek-Ivansic
Summary: In this work, cavity ring-down transient absorption spectroscopy (CRD-TAS) is introduced as a novel technique to resolve transient signals of two-dimensional samples with increased sensitivity. The successful detection of coherent artifact signals in transparent materials serves as an initial proof of concept for the CRD-TAS method. These experimental results are correlated to mathematical simulations of the nonlinear effects responsible for the coherent artifacts. By considering the purity grade of each probed material, a weighted superposition of cross-phase modulation and two photon absorption accurately reproduces the different experimental results obtained with the CRD-TAS setup. These findings lay the groundwork for further development of the CRD-TAS technique for studying excited state dynamics of optically thin samples.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Instruments & Instrumentation
Wei Wei, Alonso Castro
Summary: In this study, cavity ring-down spectroscopy (CRDS) was successfully applied to study the Er-166 isotope in an atomic beam. By using a tuned diode laser and a high-finesse ring-down optical cavity, absorbance measurements of erbium atoms were conducted with high precision. This work demonstrates the ability to study dilute atomic beams of refractory materials accurately using CRDS.
APPLIED SPECTROSCOPY
(2023)
Article
Engineering, Environmental
John W. Pohlman, Michael Casso, Cedric Magen, Emile Bergeron
Summary: The study developed a discrete sample introduction module (DSIM) for measuring methane and CO2 concentrations and delta C-13 values with a commercially available cavity ring-down spectroscopy (CRDS) analyzer. The system has a wide dynamic range and can enhance analytical performance for investigating methane and CO2 dynamics in various sample types.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Ubaid Ullah, M. Imran Cheema
Summary: The study introduces a novel sensor which uses wavelength-scanned phase shift-cavity ring down spectroscopy and linear active fiber cavity to achieve higher sensitivity than traditional fiber loop sensors. Experimental results show that by adjusting the amplifier gain, sensor sensitivity can be increased by fourteen times, with excellent agreement between experimental data and theoretical predictions.
IEEE SENSORS JOURNAL
(2021)
Article
Environmental Sciences
Cynthia Nevison, Xin Lan, Doug Worthy, Hanqin Tian
Summary: Based on the inversion results, the estimation of nitrous oxide emissions in Canada for the period of 2011-2015 is uncertain, and the overall net flux is not significantly different from zero. The emissions in Canadian cropland, mainly located in Alberta, Saskatchewan, and Manitoba, are better resolved with a total flux estimated at 0.08 +/- 0.08 Tg N/yr. The addition of 4 new Canadian sites to the inversion improves the uncertainty, but it remains large due to the low signal to background ratio at all Canadian N2O measurement sites.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Materials Science, Multidisciplinary
Qiansuo Yang
Summary: By investigating the creation of ring-down events in cavity ring-down spectroscopy through theoretical derivation and numerical simulation, the effects of frequency detuning, absorption of the medium, residual injection, and oscillation of high-order modes on ring-down time measurement are analyzed. A specific method for improvement is proposed, with results confirming the randomness in cavity field development due to limited coherence of injection light.
ADVANCED PHOTONICS RESEARCH
(2021)
Article
Chemistry, Analytical
Andrew Teggert, Harish Datta, Stephen McIntosh, Barry Warden, Simon Bateson, Fathi Abugchem, Zulfiqur Ali
Summary: Absorption is a widely used technique with lower sensitivity compared to techniques like fluorescence. Optical cavity approaches can enhance sensitivity by increasing pathlength, but have not yet been widely used for analytical applications and point-of-care diagnostics.
