Detection and analysis of volatile compounds in exhaled breath represents an attractive tool for monitoring the metabolic status a patient disease diagnosis, since it is non-invasive fast. Numerous studies have already demonstrated benefit clinical settings/applications encouraged multidisciplinary research to reveal new insights regarding origins, pathways, pathophysiological roles components. Many methods are currently available help explore these directions, ranging from mass spectrometry...

We overcome the resolution limit of Fourier-transform spectrometry and measure instrumental line-shape-free broadband molecular spectra with lines narrower than optical path-limited resolution. do this by using an frequency comb precisely matching maximum delay range spectrometer to line spacing intensities individual lines. This method allows measurements undistorted high-resolution acquisition time interferometer length reduced orders magnitude scale accuracy given comb.

Broadband precision spectroscopy is indispensable for providing high fidelity molecular parameters spectroscopic databases. We have recently shown that mechanical Fourier transform spectrometers based on optical frequency combs can measure broadband high-resolution spectra undistorted by the instrumental line shape (ILS) and with a highly precise scale provided comb. The accurate measurement of power comb modes interacting sample was achieved acquiring single-burst interferograms nominal...

We present a fast-scanning Fourier transform spectrometer (FTS) in combination with high-repetition-rate mid-infrared supercontinuum sources, covering wavelength range of 2–10.5 µm. demonstrate the performance for trace gas detection and compare various methods: baseband single photodetector, balanced detection, synchronous demodulation at repetition rate source. The FTS uses off-the-shelf optical components provides minimum spectral resolution 750 MHz. It achieves noise equivalent...

We present a versatile mid-infrared frequency comb spectroscopy system based on doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: Fourier transform spectrometer (FTS) continuous-filtering Vernier (CF-VS). Using FTS with multipass cell, we measure high precision broadband absorption spectra of CH4 at 3.3 NO 5.25 μm, latter for first time spectroscopy, detect atmospheric species (CH4, CO, CO2, H2O) air signal idler ranges. Multiline fitting...

Recent advancements of mid-infrared (MIR) supercontinuum light sources have opened up new possibilities in laser-based trace gas sensing.While the inherently support wide spectral coverage, detection broadband absorption signals with high speed and low cost is traditionally limited by MIR detector arrays.In this work, we demonstrate that limitation can be circumvented upconverting signal into near-infrared (NIR) region, where cost-effective silicon-based arrays utilized to measure...

Abstract Dual-comb spectroscopy can provide broad spectral bandwidth and high resolution in a short acquisition time, enabling time-resolved measurements. Specifically, the mid-infrared wavelength range is of particular interest, since most molecules have their strongest rotational-vibrational transitions this “fingerprint” region. Here we report dual-comb spectroscopy, covering ~300 nm around 3.3 μm with 6 GHz 20 μs temporal resolution. As demonstration, study CH 4 /He gas mixture an...

We present a multi-species trace gas sensor based on high-repetition-rate mid-infrared supercontinuum source, in combination with 30 m multipass absorption cell, and scanning grating spectrometer. The output of the spectrometer is demodulated by digital lock-in amplifier, referenced to repetition rate source. This improved detection sensitivity system factor 5, as compared direct baseband operation. provides spectral coverage 950 cm −1 (between 2.85-3.90 µm) resolution 2.5 100 ms. It can...

Supercontinuum sources based on intrapulse difference frequency generation (IDFG) from mode-locked lasers open new opportunities in mid-infrared gas spectroscopy. These provide high power and ultra-broadband spectral coverage the molecular fingerprint region with very low relative intensity noise. Here, we demonstrate performance of such a light source combination multipass cell custom-built Fourier transform spectrometer (FTS) for multispecies trace detection. The provides low-noise,...

Optical cavities provide high sensitivity to dispersion since their resonance frequencies depend on the index of refraction. We present a direct, broadband, and accurate measurement modes finesse cavity using an optical frequency comb mechanical Fourier transform spectrometer with kHz-level resolution. characterize 16000 longitudinal spanning 16 THz bandwidth in terms center frequency, linewidth, amplitude. Using we retrieve group delay mirror coatings pure N2 0.1 fs2 precision 1 accuracy,...

We demonstrate near-infrared cavity-enhanced optical frequency comb spectroscopy of water in a premixed methane/air flat flame. The detection system is based on an Er:fiber femtosecond laser, high finesse cavity containing the flame, and fast-scanning Fourier transform spectrometer (FTS). High absorption sensitivity obtained by combination high-bandwidth two-point comb-cavity lock auto-balanced FTS. allows recording high-temperature spectra with resolution 1 GHz bandwidth 50 nm acquisition...

We present a fully integrated and transportable multi-species trace gas sensor based on mid-infrared (MIR) supercontinuum light source. The high brightness (surpassing synchrotron) ultra-broad spectral bandwidth (2–4 μm) of this source allows simultaneous detection multiple broadband absorbing species. High sensitivity in the sub-ppmv level has been achieved by utilizing an astigmatic multipass cell. A grating-based spectrometer at scanning rate 20 Hz is developed employing balanced scheme....

Abstract Broadband mid-infrared (MIR) spectroscopy is a well-established and valuable diagnostic technique for reactive plasmas. Plasmas are complex systems consist of numerous (reactive) types molecules; it challenging to measure control reaction specificity with good sensitivity. Here, we demonstrate the first use novel MIR supercontinuum (SC) source quantitative plasma spectroscopy. The SC has wide spectral coverage 1300–2700 cm −1 (wavelength range 3.7–7.7 μm), thus enabling broadband...

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...

We present a multi-species trace gas sensor based on fast, compact home-built Fourier transform spectrometer (FTS) combined with broadband mid-infrared supercontinuum (SC) source. The covers the spectral bandwidth of SC source (2 - 4 µm) and provides best resolution 1 GHz in 6 seconds. It has detection sensitivity few hundred ppbv Hz -1/2 for different species. study performance developed terms precision, linearity, long-term stability, detection. use measuring fruit-produced volatiles under...

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...

We employed a single-mode, widely tunable (~300 cm−1) external-cavity quantum cascade laser operating around 8 µm for broadband direct absorption spectroscopy and wavelength modulation where frequency of 50 kHz was with high amplitudes up to 10 GHz. Using compact multipass cell, we measured the entire molecular band acetone at ~7.4 spectral resolution ~1 cm−1. In addition, demonstrate dynamic range laser, performed (DAS) second harmonic (WMS-2f) Q-branch peak (HWHM ~10 GHz) near 1365 With...

We present a new method of optical frequency comb spectroscopy that combines cavity enhancement with modulation to obtain immunity laser frequency-to-amplitude noise conversion by the modes and, thus, high absorption sensitivity over broad spectral range. A is locked free range (FSR) equal 4/3 times repetition rate laser, and phase-modulated at FSR. The transmitted light analyzed Fourier transform spectrometer bandwidth detector. Phase-sensitive detection interferogram yields noise-immune...

Conventional mechanical Fourier Transform Spectrometers (FTS) can simultaneously measure absorption and dispersion spectra of gas-phase samples. However, they usually need very long measurement times to achieve time-resolved with a good spectral temporal resolution. Here, we present mid-infrared dual-comb-based FTS in an asymmetric configuration, providing broadband resolution 5 GHz (0.18 nm at wavelength 3333 nm), 20 μs, total coverage over 300 cm−1 time ~70 s. We used the dual-comb...

An absorption spectrum of H$_2$$^{16}$O at 1950 K is recorded in a premixed methane/air flat flame using cavity-enhanced optical frequency comb-based Fourier transform spectrometer. 2417 lines are identified the 6250 -- 6670 cm region with an accuracy about 0.01 cm. Absolute line intensities retrieved temperature and concentration values obtained by tunable diode laser spectroscopy. Line assignments made combination empirically known energy levels predictions from new POKAZATEL variational...

We report broadband detection of OH in a premixed CH4/air flat flame at atmospheric pressure using cavity-enhanced absorption spectroscopy based on an Er:fiber femtosecond laserand Fourier transform spectrometer.By taking ratios spectra measured different heights above the burner we separate twenty transitions from largely overlapping water background. Weretrieve fits to lines relative variation concentration and temperature with height compare them 1-D simulations flamestructure. Full Text:...

Abstract Air pollution is one of the largest risk factors for disease or premature death globally, yet current portable monitoring technology cannot provide adequate protection at a local community level. Within TRIAGE project, smart, compact and cost-effective air quality sensor network will be developed hyperspectral detection gases which are relevant atmospheric dangerous human health. The based on mid-infrared supercontinuum source, providing ultra-bright emission across 2–10 µ m...