Extension of CO2-Laser Wavelength Range with Isotopes

Jacobs, G.; Bowers, H.C.

doi:10.1063/1.1709976

Cited by 15 publications

(5 citation statements)

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“…The CO 2 laser wavelength range is from 877 to 1086 cm −1 . 48,49 Figure (4) shows that the absorption spectrum of CHCl 3 has a spectral matching with the emission spectrum of CO 2 laser. 50 In this study, we first optimized the size and shape of the PA cell based on the equations above (Equations (1)-(8)) in order to achieve the maximum PA signal and then made it based on optimized results.…”

Section: Resultsmentioning

confidence: 84%

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High‐sensitivity detection and quantification of CHCl₃ vapors in various gas environments based on the photoacoustic spectroscopy

Mohebbifar

2019

Micro & Optical Tech Letters

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In this study, the quality factor and cell constant vs acoustic resonator sizes in the first radial and longitudinal modes were calculated using our homemade simulation. Based on these simulations a photoacoustic (PA) spectroscopy system was designed, optimized, and finally fabricated as a high‐sensitivity gas sensor. The subsequent experiments have been done to online monitoring of the trichloromethane (CHCl3) vapors trace. The sensitivity of system for detection of CHCl3 vapors was measured 488 ppb. Corresponding PA signal for different concentrations of CHCl3 vapors is determined in the presence of N2, synthetic air, He, and Ar in various gas environments. It is shown that the effect of buffer gas and the relevant pressures are substantiated to achieve the minimum detectable concentration. In other words, using heavier gases at the same experimental conditions lead to detection of the lower concentrations. When the buffer gas of system was He, the lowest PA signal was recorded. This faint signal of He is due to vibrational‐translational processes of He, thermodynamic and acoustic properties of system such as cell constant, quality factor, speed of sound, thermal diffusion, thermal boundary layer, and viscous boundary layer for He. These properties for various buffer gases were calculated and discussed.

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Section: Resultsmentioning

confidence: 84%

“…The CO 2 laser includes a mixture of N 2 and carbon dioxide gases and operates on the basis of the difference between vibrational‐rotating energy levels. The CO 2 laser wavelength range is from 877 to 1086 cm −1 . Figure () shows that the absorption spectrum of CHCl 3 has a spectral matching with the emission spectrum of CO 2 laser…”

Section: Resultsmentioning

confidence: 85%

High‐sensitivity detection and quantification of CHCl₃ vapors in various gas environments based on the photoacoustic spectroscopy

Mohebbifar

2019

Micro & Optical Tech Letters

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“…In the present work, the tunable CO 2 laser was used as the optical source with a wavelength range of 9.2-11.4 μm. 33,34 Figure 2(A),(B) show the absorption spectrum of carbonyl sulfide and ethene gases based on the HITRAN 2016 database. 35 In order to measure the limit of detection (LOD), equation of LOD ¼ C SNR was used.…”

Section: Resultsmentioning

confidence: 99%

“…In the photoacoustic spectroscopy, the sample must have an absorption line in the spectral region of the optical source. In the present work, the tunable CO 2 laser was used as the optical source with a wavelength range of 9.2–11.4 μm 33,34 . Figure 2(A),(B) show the absorption spectrum of carbonyl sulfide and ethene gases based on the HITRAN 2016 database 35…”

Section: Resultsmentioning

confidence: 99%

Ppb level detection of carbonyl sulfide and ethene and study resonant frequencies using laser photoacoustic spectroscopy

Mohebbifar

2021

Micro & Optical Tech Letters

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Laser photoacoustic spectroscopy is a laser measurement method with high sensitivity, good selectivity, nondestructive, and fast response (real‐time). In the present work, to detect carbonyl sulfide and ethene gases and measure resonant frequencies and signals, the photoacoustic spectroscopy system was designed and set up. The detection limit of this system to trace ethene and carbonyl sulfide was measured 3 ppb and 8 ppb, respectively. Also, for these two gases at the presence of different buffer gases, the resonant frequency and photoacoustic signal were recorded. The results showed that among the used buffer gases, xenon has the best acoustic performance and gives the highest photoacoustic signal. The signal also increased with increasing pressure of buffer gas, because increasing the pressure leads to improved collisional processes. The study of resonant frequencies of this system for these two gases in the presence of buffer gases showed that with increasing the pressure of xenon, argon, and nitrogen buffer gases from 65 to 765 Torr, the resonant frequency does not change significantly. But in the case of helium buffer gas, these resonant frequency changes are significant, and as the helium pressure increases by 65 to 765 Torr, the resonant frequencies of carbonyl sulfide and ethene change from 2016 to 2630 Hz and from 2100 to 2740 Hz, respectively. The reason for the different behavior of helium is the higher speed of sound in helium than in other buffer gases.

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“…The ratio of gains on the lasing transitions m CO 2 is given by g(OOOl-I) / g(OOOl-lI) = K(ooOl-I) / K (00°1-11) (2) under the good approximation that BI~BII and assumption that NI~NII. This assumption is reasonable because the energy-level difference EI-EII~ 120 cm-1 is less than kT~250 cm-1 .…”

Section: Discussionmentioning

confidence: 99%

Gain Measurements in CO2 Isotope Lasers

Silver

Hartwick

Posakony

1970

Journal of Applied Physics

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Extension of CO2-Laser Wavelength Range with Isotopes

Cited by 15 publications

References 5 publications

High‐sensitivity detection and quantification of CHCl₃ vapors in various gas environments based on the photoacoustic spectroscopy

High‐sensitivity detection and quantification of CHCl₃ vapors in various gas environments based on the photoacoustic spectroscopy

Ppb level detection of carbonyl sulfide and ethene and study resonant frequencies using laser photoacoustic spectroscopy

Gain Measurements in CO2 Isotope Lasers

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Extension of CO2-Laser Wavelength Range with Isotopes

Cited by 15 publications

References 5 publications

High‐sensitivity detection and quantification of CHCl3 vapors in various gas environments based on the photoacoustic spectroscopy

High‐sensitivity detection and quantification of CHCl3 vapors in various gas environments based on the photoacoustic spectroscopy

Ppb level detection of carbonyl sulfide and ethene and study resonant frequencies using laser photoacoustic spectroscopy

Gain Measurements in CO2 Isotope Lasers

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Product

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High‐sensitivity detection and quantification of CHCl₃ vapors in various gas environments based on the photoacoustic spectroscopy

High‐sensitivity detection and quantification of CHCl₃ vapors in various gas environments based on the photoacoustic spectroscopy