Method of guided termocleavage of glass, was developed in 80-th(1) and found wide expansion in precession breaking of glass for displays, that is proved with appropriate equipment and a wide variety of publications(1-2).
There are few advantages of this method: high speed of cutting; high accuracy in processing; low power intensity of process; high purity of process, cause of wastelessness of cutting process; zero width of cut.
Feature of this method is that cutting of glass is executed due to making of separating split under the voltage of straining, caused of the heating of material with laser radiation and next freezing of zone of heat using refrigerating medium(1-2).
The existing termocleavage technologies by means of infra-red (IR) lasers - CO2 and Nd have some insuperable constraints such as: the problem of intersection of through-the-thickness crack across previously made by laser, the problem of guided thermocrack drift from linearity upon laser emission input and output into glass samples and others problems.
We offer to use other laser radiation sources for overcoming these problems. Preview analyze showed, that the most optimal laser sources are lasers with the spectrum in the field of translucency of glasses (2-7 micron).
The process of high-intensity evaporation from the surface of quartz glass blank with use of infrared radiation of CO2 laser is considered. It is shown that the evaporation product is an amorphous SiO2 powder with particle size of 70 nm.
High monochromaticity, coherence and low divergence of the laser are the properties thanks to which it has become possible to build a promising high-concentration kind of heat energy emitter. As a source of welding energy, the laser beam has provided welding practices with new features. At present, the laser is the only available energy source that reaches power densities of more than 106 W/cm2 thus maintaining deep welding requirements.
The laser welding evolution has further developed in hybrid welding methods, such as two-beam, laser-arc, laser-induction, laser-plasma, lighting laser processing procedures that, due to their high technical and economical efficiency, find ever multiplying applications in industry.
KEYWORDS: Gas lasers, Chemical elements, Medicine, Ecology, Control systems, Laser applications, Tunable lasers, Laser metrology, High power lasers, Power supplies
An automatic output-stabilized CO-laser model tunable within a broad spectral range (-300 cm-1) and based on a sealed-off active element with life time approximately 3,000 hours has been created. Such laser find ever expanding applications to solving numerous problem sets in ecology monitoring, medicine, spectroscopy, metrology, nonlinear optics, communication systems, laser chemistry, diagnostics of active media of high-power CO lasers and
other areas.
The paper describes experimental and theoretical investigations on tunable CO2-laser-assisted measurements of the composition and concentrations in multicomponent wake behind supersonic civil aircraft.
An experimental facility based on a tunable CO2 laser and multipass cell is presented and results of experiments on determination of substances typical for civil aircraft wake (carbon and nitrogen oxides, ozone, water vapor, etc.) are given. The conditions characteristic of the aircraft wake are simulated. A possibility to perform real-time measurements of substances in question at a level of 80 ppb (80 billion-1) is demonstrated.
Calculative models were created and results of generation and evolution of substances in question in a turbulent twisted flow are reported. A mathematical model and program code were validated for numerical simulations of two-phase turbulent flow in a single trailing vortex in initial stage of contrail generation behind supersonic aircraft. The work was carried out under the project #1477 supported financially by the International Scientific-Research Center, Moscow.
A two wavelengths CO2 laser was used to determine the glucose concentration in whole blood samples. For this purpose, the first laser wavelength λ1 was tuned to the maximum of the glucose absorption band at 1080 cm-1 and the second laser wavelength λ2 was tuned to the background close to the glucose absorption band at 950 cm-1. The difference of the laser power λ1 and λ2 behind the optical cell containing the whole blood sample was determined. This signal correlates strongly with the glucose concentration in the whole blood samples.
The results of the investigation were compared to the results obtained by FTIR measurements.
CO-lasers on the basis of sealed-off active elements (SAE) with an average operational life of ~3000 hours nave a simple design and are cost-effective. They don't need gas blow off and cryogenic equipment, as well as the system of toxic gas evacuation etc. Generally, sealed-off active elements are operated at the temperatures of the cooling agent of 10°C<t<15°C. Cryogenic cooling is impossible for them, so it is interesting to perform optimization of the laser parameters at the tolerable for SAE negative temperatures. There has been performed the research on the basic output parameter of the automated modified CO-laser, which is applicable for research in medicine, ecology, active media and material study and which we described earlier, at negative temperatures of SAE up to t ~-40 °C. These measurements were made using an inexpensive standalone cooling system ("Haake Circulators"). The measurements have shown that both the width of area of spectrum modification and the power of generation at separate lines go up as the degree of cooling grows.
Rather powerful output-stabilized sealed-off cw Co-lasers tunable over lines in a wide spectral range find ever expanding applications to solving numerous problem sets in ecology monitoring, medicine, spectroscopy, metrology, nonlinear optics, communication systems, laser chemistry, diagnostics of active media of high-power CO lasers and other areas. We have created an automatic output-stabilized CO-laser model tunable within a broad spectral range (~300sm-1) and based on a sealed-off (i.e. without need for mixture flow and re-filling) active element. The main model characteristics are: total of lines to be selected for single-wave generation - about 90; tuning order - regular or irregular - to be set manually or under the program guidance and operated by computer; cw power in single strong spectral lin - up to 2,000 mW; possibility to operate both at negative and room temperatures; possibility to operate on isotopically replaced molecule CO; long- lasting output power instability - better than 1%; radiation source structure - with enhanced anti-acoustic resistivity; service life - several thousands of hours (about 3,000- 5,000).
Victor Masychev, Valentin Sysoev, Konstantin Pichkhadze, Konstantin Lezvinsky, Yuri Bulkin, Vladimir Andreev, Vladimir Eftiheev, Vladimir Rumyantzev, Ilya Tarasov, Boris Papchenko
KEYWORDS: Satellites, Laser applications, Semiconductor lasers, Laser systems engineering, Laser sources, Quantum efficiency, Control systems, Power supplies, Optical components, High power lasers
In the article the project of a laser channel of remote power transmission in space is shown. In details is circumscribed elements and system for implementation of experiment on power transmission, within the frame of the possible scientific and applied projects of experiments on the International Space Station (ISS), on a distance more than 1000 m with a level of power more than 1000 W. The capability of increase of power of radiation is shown. The capability of reaching efficiency of a channel of power transmission up to 30% is designed. Also in the article a number of possible additional applications of the given system-data transfer with high speed and measurement of geometric parameters of interposition satellite-satellite is shown. The article contains analysis of using a channel power transmission for information-measuring whole.
The present paper is concerned with automatic optimization of tunable CO2 laser emission power that has been realized by changing the in-resonator polarization direction. We have begun with the investigation into the experimental reflection efficiency of the grating in use for first and zero diffraction orders as a function of the incident polarization plane orientation relative to the grating line length obtained from the first-order Littrow system. The dependencies measured were then used to determined the angle ?(J) between the grating line length and the polarization vector such that the zero-order reflection factor was equal to its optimal value that is a function ofthe active medium gain for the J-th line, active length, and useless loss inside the laser cavity. After this, the monitoring and control software of the laser has been enhanced with the ?(J)-values found out in accordance with the above procedure for each laser line associated with its intrinsic gain. Hence, the laser tuning in J-th line is accompanied with automatic orientation ofthe Brewster window at the angle ?(J). Due to the given optimization we were able to acquire for each particular line the highest power at the maximum line amount in the output spectrum.
A novel automatic output stabilized tunable CO2 laser has been developed providing a new quality level of investigations in the areas of atmosphere monitoring, active media diagnostics, spectroscopy, etc. The optimally designed and arranged laser is composed of sites and systems with reliable operational resources. Mean time till failure of the laser is 1000 h. About 0.3 cm-1 resolution of its high-Q and highly selective resonator allows extraction of most lines in sequence and hot bands without using a hot cell in the laser cavity. The laser is also distinguished among many other lasers by generating a high power (up to 50 W) at traditional lines and a great amount (near 160 totally) of sequence and hot lines (up to 10 W) in the 9 - 12 micrometers range which can be qualitatively changed in favor of sequence or hot lines by replacing some of the sealed-off active element or the whole set of them. Software and hardware developed for handling the laser operation offer the possibility to extract a needed set of lines in any succession and with a required run duration.
The gains were measured for the lines in the traditional band 0001-1000, 0001-0200, in the second band of the 0002-1001 sequence, and in the hot band 0111- 1110 emitted by the active medium of an electric-discharge carbon-dioxide module. The experimental results were used in a generalized theoretical model to find the translation and vibrational temperatures and the concentration of the active molecules. The Fermi resonance between the 1000 and 0200 did not ensure a Boltzmann distribution of their populations under the conditions in the electric-discharge module. The degree of dissociation of the carbon-dioxide molecules in the discharge did not exceed 22% when the maximum input power density was near 6 W/cm3.
Studying the optimum performance of molecular lasers requires information.on active medium parameters. Those in case of laser are translational and vibrational temperatures T, T1 , T2, T3' , and lasing molecule concentration., n. Vibrational temperatures have previously been determined in series investigations of electro discharge CO—laser active medium234S. But definition of concentration n potentially associated with large errors due to lack of lower laser level's vibrational temperature T1 measurements. Other temperatures have been estimated according to approximate model. As it was theoretically shown6 , to determine the inverse medium parameters without simplification, one should measure the small signal gains for lines of (0001_1000) and (0001_0200) traditional CO2 bands, (0002_1001) second sequence band and (O1'l-ll'O) hot band. Translational and vibrational temperatures and lasing molecule concentration were defined for CO—laser using the small signal gain measurements and theoretical scheme6.
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