Infrared Absorption Spectroscopy

Fried, Alan; Richter, Dirk

doi:10.1002/9780470988510.ch2

Cited by 50 publications

(41 citation statements)

References 120 publications

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“…One of the primary motivations for employing mid-infrared laser sources for trace gas detection is to access the strongest fundamental absorption bands of molecules which significantly increases detection sensitivities. These laser sources include lead salt diode lasers, quantum cascade (QC) semiconductor lasers, and laser sources based upon nonlinear optical frequency conversion, including continuous wave difference-frequency generation (DFG) and optical parametric oscillators (OPO) [1,2].…”

Section: Introductionmentioning

confidence: 99%

Difference frequency generation laser based spectrometers

Richter¹,

Fried

Weibring

2009

Laser & Photonics Reviews

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Tunable mid-infrared laser sources are the key to precision optical trace gas detection. Difference-frequency generation (DFG) based laser sources are among a few practical laser sources that have demonstrated ultra-high detection sensitivities during real-world applications when combined with appropriate signal enhancing and noise reduction spectroscopic techniques. This article will discuss the technical approaches, illustrate application examples of DFG sources, and offer perspectives to competing technologies.A He-Ne alignment laser visualizes a reentrant beam pattern of a 100 m, 182 pass astigmatic Herriott multi-pass absorption cell used in highly sensitive trace gas DFG spectrometers.

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Section: Introductionmentioning

confidence: 99%

Difference frequency generation laser based spectrometers

Richter¹,

Fried

Weibring

2009

Laser & Photonics Reviews

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“…38 In conventional TDLAS, the frequency of the probing laser is swept across an absorption feature, which encodes the spectroscopic information in the attenuated intensity. Similarly, in swept direct absorption MHS, both lasers are rapidly swept across a narrowband transition (<1 GHz), while the amplitude of their resulting beat note is analyzed.…”

Section: Narrowband Multiheterodyne Spectroscopymentioning

confidence: 99%

Multiheterodyne spectroscopy using interband cascade lasers

et al. 2017

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Abstract. While midinfrared radiation can be used to identify and quantify numerous chemical species, contemporary broadband midinfrared spectroscopic systems are often hindered by large footprints, moving parts, and high power consumption. In this work, we demonstrate multiheterodyne spectroscopy (MHS) using interband cascade lasers, which combines broadband spectral coverage with high spectral resolution and energy-efficient operation. The lasers generate up to 30 mW of continuous-wave optical power while consuming <0.5 W of electrical power. A computational phase and timing correction algorithm is used to obtain kHz linewidths of the multiheterodyne beat notes and up to 30 dB improvement in signal-to-noise ratio. The versatility of the multiheterodyne technique is demonstrated by performing both rapidly swept absorption and dispersion spectroscopic assessments of low-pressure ethylene (C 2 H 4 ) acquired by extracting a single beat note from the multiheterodyne signal, as well as broadband MHS of methane (CH 4 ) acquired with all available beat notes with microsecond temporal resolution and an instantaneous optical bandwidth of ∼240 GHz. The technology shows excellent potential for portable and high-resolution solid-state spectroscopic chemical sensors operating in the midinfrared.

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“…Diode lasers were early recognized as suitable light sources for gas-absorption spectroscopy due to their reliability, compact size, and wavelength tunability, and are today a natural component in many gas sensors [1][2][3]. High sensitivity and selectivity of tunable diode laser absorption spectroscopy, TDLAS, makes it a fast chemical analysis tool which is used both in industry [4] and in various research fields [5].…”

Section: Introductionmentioning

confidence: 99%

Fast and sensitive time-multiplexed gas sensing of multiple lines using a miniature telecom diode laser between 1529 nm and 1565 nm

et al. 2011

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High-sensitive multi-species detection around 1550 nm using a modulated grating Y-branch, MG-Y, diode laser tunable between 1529 nm and 1565 nm is presented. The MG-Y diode laser is based on the Vernier effect of two modulated gratings, and exhibits quasi-continuous tuning over 36 nm. Multi-species detection is achieved by fast sequential scanning of single absorption lines of CH 4 , CO, C 2 H 2 , and CO 2 distributed over the tuning range of the diode laser. The laser wavelength is scanned about 10 GHz around each absorption line for 5 ms and this is followed by a discrete large jump in operating wavelength to the next line.The MG-Y diode laser has a good repeatability in output frequency between sequential scan segments (<10 MHz) enabling averaging of the scans. The setup employs digital wavelength modulation spectroscopy, dWMS, with Fourier-

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Infrared Absorption Spectroscopy

Cited by 50 publications

References 120 publications

Difference frequency generation laser based spectrometers

Difference frequency generation laser based spectrometers

Multiheterodyne spectroscopy using interband cascade lasers

Fast and sensitive time-multiplexed gas sensing of multiple lines using a miniature telecom diode laser between 1529 nm and 1565 nm

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