Quasi-Continuous Wave Stimulated Raman Technique for Local Methane Concentration Measurements at Atmospheric Pressure

We report the application of quasi-continuous wave (cw) inverse stimulated Raman spectroscopy (SRS) to the quantitative measurement of methane concentrations in atmospheric mixtures near room temperature. The quasi-cw SRS signal, with the use of the v1, fundamental of methane (2916 cm−1), is shown to be proportional to the powers of both the pump and probe lasers as well as to the methane concentration. The current minimum detectable signal corresponds to ∼200 ppm (v/v).

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Photoacoustic Detection of Short-Chained Hydrocarbon Isotopologues

Proceedings ◽

10.3390/proceedings2019015023 ◽

2019 ◽

Vol 15 (1) ◽

pp. 23

Author(s):

Loh ◽

Wolff

Keyword(s):

Atmospheric Pressure ◽

Room Temperature ◽

Continuous Wave ◽

Stable Carbon Isotope ◽

Distributed Feedback ◽

Light Sources ◽

Photoacoustic Detection ◽

Optoacoustic Spectroscopy ◽

Interband Cascade Lasers ◽

Cascade Lasers

We report, to our knowledge, the first optical detection of the main isotopologues of short-chained hydrocarbons. The sensor system is based on photoacoustic (also known as optoacoustic) spectroscopy (PAS, OAS). This technique takes advantage of the fact that absorbed electromagnetic radiation is partially transferred into kinetic energy via inelastic molecular collisions. This is equivalent to a temperature increase of the irradiated volume. If the radiation is modulated, a pressure wave with an amplitude proportional to the concentration of the absorbing molecules is generated, the so called PA (OA) signal. Two continuous wave (cw), thermoelectrically cooled (TEC), distributed feedback interband cascade lasers (DFB-ICLs) with emission wavelengths around 3.33 and 3.38 μm, respectively, serve as light sources. The PA signal is detected with a microphone and phase-sensitively amplified. The new sensor is applied for the stable carbon isotope-selective analyses of methane (CH4), ethane (C2H6) and propane (C3H8). We report first measurements of 12C2H6, 13C12CH6 and 13C2H6 as well as of 12C3H8 and 13C12C2H8, all at approximate room temperature and atmospheric pressure. The listed isotopologues were selected because of their importance for numerous applications from atmospheric and planetary research to natural gas exploration.

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Room‐temperature continuous‐wave operation of an AlGaInP double heterostructure laser grown by atmospheric pressure metalorganic chemical vapor deposition

Applied Physics Letters ◽

10.1063/1.96366 ◽

1985 ◽

Vol 47 (10) ◽

pp. 1027-1028 ◽

Cited By ~ 106

Author(s):

Masao Ikeda ◽

Yoshifumi Mori ◽

Hiromitsu Sato ◽

Kunio Kaneko ◽

Naozo Watanabe

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Atmospheric Pressure ◽

Room Temperature ◽

Metalorganic Chemical Vapor Deposition ◽

Continuous Wave ◽

Chemical Vapor ◽

Heterostructure Laser ◽

Continuous Wave Operation ◽

Metalorganic Chemical

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Continuous wave stimulated Raman spectroscopy of the ν1 band of natural GeH4

Journal of Raman Spectroscopy ◽

10.1002/jrs.1250130310 ◽

1982 ◽

Vol 13 (3) ◽

pp. 257-261 ◽

Cited By ~ 23

Author(s):

S. Q Mao ◽

R. Saint-Loup ◽

A. Aboumajd ◽

P. Lepage ◽

H. Berger ◽

...

Keyword(s):

Raman Spectroscopy ◽

Continuous Wave ◽

Stimulated Raman

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Accurate and Traceable Determination of Raman Shifts in Reference Material by Continuous-Wave Stimulated Raman Spectroscopy

2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) ◽

10.1109/cleoe-eqec.2019.8871471 ◽

2019 ◽

Author(s):

Hugo Kerdoncuff ◽

Mikael Lassen ◽

Jan C. Petersen

Keyword(s):

Raman Spectroscopy ◽

Reference Material ◽

Continuous Wave ◽

Stimulated Raman

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Stimulated Raman spectroscopy of theQbranch of nitrogen at high pressure: collisional narrowing and shifting in the 150–6800 bar range at room temperature

Molecular Physics ◽

10.1080/00268979200100311 ◽

1992 ◽

Vol 75 (2) ◽

pp. 397-413 ◽

Cited By ~ 42

Author(s):

B. Lavorel ◽

B. Oksengorn ◽

D. Fabre ◽

R. Saint-Loup ◽

H. Berger

Keyword(s):

Raman Spectroscopy ◽

High Pressure ◽

Room Temperature ◽

Stimulated Raman

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First demonstration of surface enhanced-stimulated Raman spectroscopy (SE-SRS) using low-power CW sources

Faraday Discussions ◽

10.1039/c7fd00137a ◽

2017 ◽

Vol 205 ◽

pp. 227-232 ◽

Cited By ~ 2

Author(s):

C. L. D. Lee ◽

K. C. Hewitt

Keyword(s):

Raman Spectroscopy ◽

Continuous Wave ◽

Low Noise ◽

Wave Surface ◽

Ti:Sapphire Lasers ◽

Surface Enhanced ◽

Lock In ◽

First Time ◽

532 Nm ◽

Stimulated Raman

Using commercially available nanoparticles, continuous wave Surface-Enhanced Stimulated Raman spectroscopy (CW SE-SRS) is demonstrated for the first time using two Ti:Sapphire lasers producing a pump beam (785 nm, 100 mW) and appropriately varying probe/Stokes beams (860–870 nm, 120 mW). The Ti-Sapphire lasers are co-pumped by a 10 W low noise 532 nm Spectra Physics Millennia laser. Pulsed SE-SRS is also demonstrated using a Coherent Chameleon Ultra laser for the Stokes/probe (863–871 nm) beam and a Coherent Ultra II as the pump laser (785 nm). In both cases lock-in techniques are used to extract the small signal (1 in 109) successfully. These experiments convincingly demonstrate that SRS with CW sources is possible using appropriate nanoparticles, and this realization creates opportunities for a wider range of stimulated Raman spectroscopy applications.

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