CO2 laser photoacoustic measurements of ethanol absorption coefficients within infrared region of 9.2–10.8μm

2016 ◽  
Vol 163 ◽  
pp. 115-119 ◽  
Author(s):  
I.R. Ivascu ◽  
C.E. Matei ◽  
M. Patachia ◽  
A.M. Bratu ◽  
D.C. Dumitras
Keyword(s):  
Co2 Laser ◽  
Infrared Region ◽  
Absorption Coefficients

scholarly journals CO2 Laser Photoacoustic Spectrometer for Measuring Acetone in the Breath of Lung Cancer Patients

Biosensors ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 55 ◽  
Author(s):  
Mitrayana ◽  
Donni Kis Apriyanto ◽  
Mirza Satriawan
Keyword(s):  
Lung Cancer ◽  
Co2 Laser ◽  
Infrared Region ◽  
Absorption Coefficients ◽  
Human Breath ◽  
Cancer Disease ◽  
Measurement Capability ◽  
Lung Cancer Patients ◽  
Photoacoustic Spectrometer ◽  
Small Absorption

A CO2 laser has the advantages of being high in power and having many laser lines in the 9–11 µm infrared region. Thus, a CO2 laser photoacoustic spectrometer (PAS) can have a multi-component measurement capability for many gas compounds that have non-zero absorption coefficients at the laser lines, and therefore can be applied for measuring several volatile organic compounds (VOCs) in the human breath. We have developed a CO2 laser PAS system for detecting acetone in the human breath. Although acetone has small absorption coefficients at the CO2 laser lines, our PAS system was able to obtain strong photoacoustic (PA) signals at several CO2 laser lines, with the strongest one being at the 10P20 line. Since at the 10P20 line, ethylene and ammonia also have significant absorption coefficients, these two gases have to be included in a multi-component measurement with acetone. We obtained the lowest detection limit of our system for the ethylene, acetone, and ammonia are 6 ppbv, 11 ppbv, and 31 ppbv, respectively. We applied our PAS system to measure these three VOCs in the breath of three groups of subjects, i.e., patients with lung cancer disease, patients with other lung diseases, and healthy volunteers.

The Electrically Controlled Birefringence Measurement Influence of Liquid Crystal Caused by Absorption Effect in Infrared Region

2014 ◽  
Vol 875-877 ◽  
pp. 467-471
Author(s):  
Ning Wang ◽  
Xiao Xia Li
Keyword(s):  
Liquid Crystal ◽  
Absorption Coefficient ◽  
Approximate Method ◽  
Nematic Liquid Crystal ◽  
Infrared Region ◽  
Interference Method ◽  
Absorption Coefficients ◽  
Absorption Effect ◽  
Ordinary Light

The electrically controlled birefringence of nematic liquid crystal BL-009 was measured by polarized interference method. The influence of LC absorption effect, the birefringence variation, is discussed in this paper. The experiments results showed the influence to birefringence is big in infrared region. Not only the birefringence value is greatly different with that of unconsidering absorption effect, but also the gradient changing of birefringence curves is obvious. Furthermore, the electrically controlled birefringences of two conditions are compared when the absorption coefficients of ordinary light and the extraordinary light are nearly same and greatly different. The analysis demonstrated the approximate method of absorption coefficient is feasible.

The Use of Reverse Mirage Spectroscopy to Determine the Absorption Coefficient of Liquid Methanol at CO2 Laser Wavelengths

1989 ◽  
Vol 43 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Dane Bićanić ◽  
Siegfried Krüger ◽  
Paul Torfs ◽  
Bruno Bein ◽  
Frans Harren
Keyword(s):  
Absorption Coefficient ◽  
Co2 Laser ◽  
Probe Beam ◽  
Laser Emission ◽  
Wavelength Region ◽  
Experimental Setup ◽  
Absorption Coefficients ◽  
Experimental Conditions ◽  
Liquid Samples

An experimental setup for performance of reverse mirage spectroscopy at CO2 laser wavelengths on liquid samples having high values of absorption coefficients is described. One and the same liquid is used as both the absorbing and deflecting medium. The Rosencwaig-Gersho theory has been applied, and the choice of experimental conditions that would enable determination of absorption coefficient β from the magnitude of photothermal signals measured at two different probe beam distances (probing locations) is discussed. The usefulness of this technique (essentially not inhibited by the requirements imposed on the sample's thickness) is tested on methanol having absorption coefficients β close to 300 cm−1 in the wavelength region covered by CO2 laser emission.

Comments on absolute absorption coefficients of atmospheric water vapor at CO2 laser wavelengths

1987 ◽  
Vol 27 (5) ◽  
pp. 345-347 ◽  
Author(s):  
P.L. Meyer ◽  
M.W. Sigrist ◽  
F.K. Kneubühl ◽  
J. Hinderling
Keyword(s):  
Water Vapor ◽  
Co2 Laser ◽  
Atmospheric Water Vapor ◽  
Atmospheric Water ◽  
Absorption Coefficients

Transferring the high accuracy of the 10μm CO2 laser bands to far infrared region with internal calibration of CS2

2005 ◽  
Vol 229 (1) ◽  
pp. 89-107 ◽  
Author(s):  
V.-M. Horneman ◽  
R. Anttila ◽  
J. Pietilä ◽  
S. Alanko ◽  
M. Koivusaari
Keyword(s):  
Co2 Laser ◽  
Far Infrared ◽  
Infrared Region ◽  
High Accuracy ◽  
Internal Calibration

Temperature dependence of the linewidth of the CO2 laser transitions

1980 ◽  
Vol 58 (4) ◽  
pp. 512-515 ◽  
Author(s):  
A. M. Robinson ◽  
J. S. Weiss
Keyword(s):  
Temperature Dependence ◽  
Co2 Laser ◽  
Line Center ◽  
Absorption Coefficients ◽  
Temperature Range ◽  
Experimental Values

Comparison of calculated and experimental values of the line-center absorption coefficients of the R(10)–R(24) 10.4 μm CO2 laser transitions has been performed to determine how the pressure-broadened linewidth varies with temperature. Assuming the linewidth varies as T−x, calculation and experiment agree most closely for [Formula: see text] over the temperature range 300–650 K.

Absorption coefficients of O3 at CO2 laser wavelengths

2003 ◽  
Vol 39 (5-6) ◽  
pp. 619-627 ◽  
Author(s):  
J. Codnia ◽  
M.L. Azcárate
Keyword(s):  
Co2 Laser ◽  
Absorption Coefficients

Determination of Scattering and Absorption Coefficients of Porous Silica Aerogel Composites

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Tairan Fu ◽  
Jiaqi Tang ◽  
Kai Chen ◽  
Fan Zhang
Keyword(s):  
Silica Aerogel ◽  
Sol Gel ◽  
Porous Silica ◽  
Infrared Region ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Absorption Coefficients ◽  
Surface Reflection ◽  
Radiation Propagation ◽  
Hemispherical Reflectance

Silica aerogels are porous ultralight materials with exceptional physical properties that are promising materials for thermal insulation applications. This paper theoretically and experimentally investigates the spectral scattering and absorption coefficients of a porous silica aerogel. Silica aerogel samples were prepared with the same compositions and various thicknesses using the sol-gel technique and supercritical drying. The spectral normal-hemispherical transmittances and reflectances of the silica aerogel samples with various thicknesses were measured for wavelengths of 0.38–15 μm. The reflectance and transmittance are higher at short wavelengths than in the infrared region due to the strong scattering and weak absorption at short wavelengths. The thicker samples strongly attenuate the spectral normal-hemispherical transmittance, but have little effect on the spectral normal-hemispherical reflectance. A modified two-flux radiative transfer model was used to analyze the radiation propagation in the silica aerogel with a rough surface morphology and millimeter thicknesses to develop theoretical expressions for the spectral directional-hemispherical reflectance and transmittance. Then, the optical constants, including the absorption coefficient and the scattering coefficient, were determined for wavelengths of 0.38–15 μm based on experimental data by the least-squares algorithm. The results show that when considering the radiation propagation inside the sample, the surface reflection at the air–aerogel interface can be neglected for aerogel thicker than 1.1 mm when the absorbing and scattering effects inside the sample are quite important. The analysis provides valuable data for the optical properties for silica aerogel applications.

Sign in / Sign up

Export Citation Format

Share Document