Detection of PH3 with the help of a CO2 laser and stark modulation of the absorption coefficient

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.

Download Full-text

Modeling of CO2 Gas Excitation Under CO2 Laser Irradiation

Heat Transfer, Volume 2 ◽

10.1115/imece2006-15625 ◽

2006 ◽

Author(s):

Lan Jiang ◽

Hai-Lung Tsai

Keyword(s):

Absorption Coefficient ◽

Co2 Laser ◽

Population Distribution ◽

Boltzmann Distribution ◽

Laser Wavelength ◽

Equilibrium States ◽

Published Data ◽

Co2 Absorption ◽

Co2 Gas ◽

Laser Coating

Lasers especially multiple laser beams demonstrate unique advantages as energy sources in diamond synthesis. However, the fundamental mechanisms involved in the laser-assisted processes are not Well understood. In a reported amazingly-fast multiple laser coating technique, CO2 gas is claimed as the sole precursor or secondary precursor, which remains poorly understood and unverified. The absorption coefficient changes under the irradiation of the multiple lasers are one of the keys to resolve the mysteries of multiple laser beam coating processes. This study investigates the optical absorption in CO2 gas at the CO2 laser wavelength. This resonance absorption process is modeled as an inverse process of the lasing transitions of CO2 lasers. The well-established CO2 vibrational-rotational energy structures are used as the basis for the calculations with the Boltzmann distribution for equilibrium states and the three-temperature model for non-equilibrium states. Based on the population distribution, our predictions of CO2 absorption coefficient changes as the function of temperature are in agreement with the published data.

Download Full-text

High temperature absorption on the P(26)–P(32) CO2 laser transitions

Canadian Journal of Physics ◽

10.1139/p79-261 ◽

1979 ◽

Vol 57 (11) ◽

pp. 1896-1897 ◽

Cited By ~ 2

Author(s):

A. M. Robinson

Keyword(s):

High Temperature ◽

Absorption Coefficient ◽

Co2 Laser ◽

Line Center

The line-center absorption coefficient of CO2, has been measured as a function of temperature from 295 to 650 K for the P(26)–P(32) laser transitions.

Download Full-text

Study the effect by CO2 laser on some optical properties of (Cd) thin film doping by Ni

Baghdad Science Journal ◽

10.21123/bsj.5.3.387-390 ◽

2008 ◽

Vol 5 (3) ◽

pp. 387-390

Author(s):

Baghdad Science Journal

Keyword(s):

Thin Films ◽

Optical Properties ◽

Absorption Coefficient ◽

Co2 Laser ◽

Energy Gap ◽

Hexagonal Structure ◽

X Ray Diffraction ◽

X Ray ◽

Before And After ◽

Cds Thin Films

In this research study the effect of irradiation by (CW) CO2 laser on some optical properties of (Cds) doping by Ni thin films of (1)µm thickness has been prepared by heat evaporation method. (X-Ray) diffraction technique showed the prepared films before and after irradiation are ploy crystalline hexagonal structure, optical properties were include recording of absorbance spectra for prepared films in the range of (400-1000) nm wave lengths, the absorption coefficient and the energy gap were calculated before and after irradiation, finally the irradiation affected (CdS) thin films by changing its color from the Transparent yellow to dark rough yellow and decrease the value absorption coefficient also increase the value of energy gap.

Download Full-text

Numerical Modeling of CO2 Laser-Heated Moving Glass Rods

Heat Transfer, Volume 5 ◽

10.1115/imece2002-33082 ◽

2002 ◽

Author(s):

Weixue Tian ◽

Wilson K. S. Chiu

Keyword(s):

Temperature Distribution ◽

Absorption Coefficient ◽

Laser Irradiation ◽

Co2 Laser ◽

Radiation Heat Transfer ◽

Critical Diameter ◽

High Absorption Coefficient ◽

Glass Rods ◽

Volume Method ◽

Laser Heated

A numerical model is introduced to calculate the temperature field in moving glass rods heated by CO2 laser irradiation at a wavelength of 10.6 μm. The glass is assumed to be opaque to laser irradiation due to its high absorption coefficient at 10.6 μm. The dependence of the absorption coefficient on wavelength and temperature is considered in this model. The diffusion approximation is incorporated to analyze the radiation heat transfer in the glass rod. This approximation is valid when the glass rod is above a critical diameter. The temperature within the glass is solved using the finite volume method. The effect of laser power, laser focus, the moving speed and the radius of glass rod on the temperature distribution are studied. It is found that all these parameters have a significant effect on the temperature distribution in the glass rod. Results of simulation show that, with careful choice of these parameters, a CO2 laser may be used as a heat source for glass rod annealing or coating with stringent temperature constraints.

Download Full-text

Effect of CO2-laser power density on the absorption coefficient of polycrystalline CVD diamonds

Quantum Electronics ◽

10.1070/qel17423 ◽

2020 ◽

Vol 50 (12) ◽

pp. 1140-1145

Author(s):

M.S. Andreeva ◽

N.V. Artyushkin ◽

M.I. Krymskii ◽

A.I. Laptev ◽

N.I. Polushin ◽

...

Keyword(s):

Absorption Coefficient ◽

Power Density ◽

Co2 Laser ◽

Laser Power ◽

Laser Power Density

Download Full-text

Is there a “universal” MAC equation?

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134740 ◽

1990 ◽

Vol 48 (2) ◽

pp. 228-229

Author(s):

Robert E. Ogilvie

Keyword(s):

Absorption Coefficient ◽

Atomic Absorption ◽

Atomic Number ◽

X Ray ◽

Time Period ◽

Image Position

The search for an empirical absorption equation begins with the work of Siegbahn (1) in 1914. At that time Siegbahn showed that the value of (μ/ρ) for a given element could be expressed as a function of the wavelength (λ) of the x-ray photon by the following equationwhere C is a constant for a given material, which will have sudden jumps in value at critial absorption limits. Siegbahn found that n varied from 2.66 to 2.71 for various solids, and from 2.66 to 2.94 for various gases.Bragg and Pierce (2) , at this same time period, showed that their results on materials ranging from Al(13) to Au(79) could be represented by the followingwhere μa is the atomic absorption coefficient, Z the atomic number. Today equation (2) is known as the “Bragg-Pierce” Law. The exponent of 5/2(n) was questioned by many investigators, and that n should be closer to 3. The work of Wingardh (3) showed that the exponent of Z should be much lower, p = 2.95, however, this is much lower than that found by most investigators.

Download Full-text