Widely tunable mode-hop free external cavity quantum cascade laser for high resolution spectroscopic applications

Wysocki, Gerard; Curl, R. F.; Tittel, Frank K.; Maulini, Richard; Bulliard, Jean-Marc; Faist, Jérôme

doi:10.1007/s00340-005-1965-4

Cited by 223 publications

(117 citation statements)

References 16 publications

Supporting

Mentioning

117

Contrasting

Order By: Relevance

“…While the reduced sensitivity (smaller signals) makes interferometric absorption measurements more prone to detector noise, they are much less susceptible to intensity noise due to the reduced levels of background intensity at the detector. This is of particular interest for external cavity laser based spectroscopy, since these lasers are known for intensity noise associated with mode hops [10,24]. A trade-off between sensitivity and immunity to intensity noise can be made by unbalancing the intensities of the reference and sample beam.…”

Section: Discussionmentioning

confidence: 99%

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

et al. 2018

View full text Add to dashboard Cite

We employ a novel spectroscopic setup based on an external cavity quantum cascade laser and a Mach-Zehnder interferometer to simultaneously record spectra of absorption and dispersion of liquid samples in the mid-infrared. We describe the theory underlying the interferometric measurement and discuss its implications for the experiment. The capability of simultaneously recording a refractive index and absorption spectrum is demonstrated for a sample of acetone in cyclohexane. The recording of absorption spectra is experimentally investigated in more detail to illustrate the method's capabilities as compared to direct absorption spectroscopy. We find that absorption signals are recorded with strongly suppressed background, but with smaller absolute sensitivity. A possibility of optimizing the setup's performance by unbalancing the interferometer is presented.

show abstract

Section: Discussionmentioning

confidence: 99%

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Overall, external cavity quantum cascade lasers (EC-QCLs) [13][14][15] represents a light source with high power, broad tuning range, narrow linewidth, and rapid wavelength tuning for the sensitive and accurate detection of trace gases like in breath analysis [16,17]. Examples of applications using EC-QCLs in narrowband absorption include detection of exhaled acetone [18,19], ammonia [20] and nitric oxide [21].…”

Section: Introductionmentioning

confidence: 99%

Influence of Ethanol on Breath Acetone Measurements Using an External Cavity Quantum Cascade Laser

et al. 2016

View full text Add to dashboard Cite

Broadly tunable external cavity quantum cascade lasers (EC-QCLs) in combination with off-axis integrated cavity enhanced spectroscopy (OA-ICOS) provide high molecular gas sensitivity and selectivity. We used an EC-QCL in the region of 1150-1300 cm´1 in both broadband scan mode, as well as narrow scanning mode around 1216 cm´1, respectively, for detection of acetone in exhaled breath. This wavelength region is essential for accurate determination of breath acetone due to the relative low spectral influence of other endogenous molecules like water, carbon dioxide or methane. We demonstrated that ethanol has a strong spectroscopic influence on the acetone concentration in exhaled breath, an important detail that has been overlooked so far. An ethanol correction is proposed and validated with the reference measurements from a proton-transfer reaction mass spectrometer (PTR-MS) for the same breath samples from ten persons. With the ethanol correction, both broadband and narrowband molecular spectroscopy represent an attractive way to accurately assess the exhaled breath acetone. The importance of considering spectroscopic ethanol influence is essential, especially for the narrowband scans, (e.g., 1216 cm´1), for which the error in determining the acetone concentrations can rise up to 39% if it is not considered.

show abstract

“…Single-mode operation can be achieved by processing QCLs as DFB lasers [8], or by incorporating QCLs within an external cavity with a rotating diffraction grating that provides tunable, single-mode operation [9], [10]. External cavity versions are broadly tunable (over 200 cm ) but complex to build, requiring careful alignment and high-quality antireflection coatings.…”

mentioning

confidence: 99%

DFB Quantum Cascade Laser Arrays

Lee

Belkin

Pflügl

et al. 2009

IEEE J. Quantum Electron.

102

110

View full text Add to dashboard Cite

Abstract-DFB quantum cascade laser (DFB-QCL) arrays operating between 8.7 and 9.4 m are investigated for their performance characteristics-single-mode selection of the DFB grating, and variability in threshold, slope efficiency, and output power of different lasers in the array. Single-mode selection refers to the ability to choose a desired mode/frequency of laser emission with a DFB grating. We apply a theoretical framework developed for general DFB gratings to analyze DFB-QCL arrays. We calculate how the performance characteristics of DFB-QCLs are affected by the coupling strength of the grating, and the relative position of the mirror facets at the ends of the laser cavity with respect to the grating. We discuss how single-mode selection can be improved by design. Several DFB-QCL arrays are fabricated and their performance examined. We achieve desired improvements in single-mode selection, and we observe the predicted variability in the threshold, slope efficiency, and output power of the DFB-QCLs. As a demonstration of potential applications, the DFB-QCL arrays are used to perform infrared absorption spectroscopy with fluids.Index Terms-DFB lasers, infrared spectroscopy, mid-infrared, quantum cascade lasers (QCLs), semiconductor lasers.

show abstract

Widely tunable mode-hop free external cavity quantum cascade laser for high resolution spectroscopic applications

Cited by 223 publications

References 16 publications

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

A quantum cascade laser-based Mach–Zehnder interferometer for chemical sensing employing molecular absorption and dispersion

Influence of Ethanol on Breath Acetone Measurements Using an External Cavity Quantum Cascade Laser

DFB Quantum Cascade Laser Arrays

Contact Info

Product

Resources

About