Carbon dioxide lasers

Fig. 6. Carbon dioxide laser construction (a) original configuration having longitudinal electric (E) field and gas flow (b) advanced configuration having...

The transversely excited atmospheric-pressure (TEA) laser, inherently a pulsed device rather than a continuous laser, is another common variety of carbon dioxide laser (33,34). Carbon dioxide—TEA lasers are an important class of high-power pulsed lasers. Pulse durations are in the submicrosecond regime peak powers exceed 10 MW. 

Laser Photochemistry. Photochemical appHcations of lasers generally employ tunable lasers which can be tuned to a specific absorption resonance of an atom or molecule (see Photochemical technology). Examples include the tunable dye laser in the ultraviolet, visible, and near-infrared portions of the spectmm the titanium-doped sapphire, Tfsapphire, laser in the visible and near infrared optical parametric oscillators in the visible and infrared and Line-tunable carbon dioxide lasers, which can be tuned with a wavelength-selective element to any of a large number of closely spaced lines in the infrared near 10 ]lni. 

This reaction has been carried out with a carbon dioxide laser line tuned to the wavelength of 10.61 p.m, which corresponds to the spacing of the lowest few states of the SF ladder. The laser is a high power TEA laser with pulse duration around 100 ns, so that there is no time for energy transfer by coUisions. This example shows the potential for breakup of individual molecules by a tuned laser. As with other laser chemistry, there is interest in driving the dissociation reaction in selected directions, to produce breakup in specific controllable reaction channels. 

The laser spray process uses a high power carbon dioxide laser focused onto the surface of the part to be metallized. A carrier gas such as belium blows metal particles into the path of the laser and onto the part. The laser melted particles may fuse to the surface, or may be incorporated into an aHoy in a molten surface up to 1-mm thick. The laser can be used for selective aHoying of the surface, for production of amorphous coatings, or for laser hardening. 

A unique problem arises when reducing the fissile isotope The amount of that can be reduced is limited by its critical mass. In these cases, where the charge must be kept relatively small, calcium becomes the preferred reductant, and iodine is often used as a reaction booster. This method was introduced by Baker in 1946 (54). Researchers at Los Alamos National Laboratory have recently introduced a laser-initiated modification to this reduction process that offers several advantages (55). A carbon dioxide laser is used to initiate the reaction between UF and calcium metal. This new method does not requite induction heating in a closed bomb, nor does it utilize iodine as a booster. This promising technology has been demonstrated on a 200 g scale. 

A carbon dioxide laser produces radiation of wavelength 106 micrometers (1 micrometer = 10-6 meter). If the laser produces about one joule of energy per pulse, how many photons are produced per pulse ... 

Garrett AB, Dufresne RG Jr, Ratz JL, Berlin AJ (1990) Carbon dioxide laser treatment of pitted acne scarring. J Dermatol Surg Oncol 16 737-740... 

Alster TS, West TB (1996) Resurfacing of atrophic facial acne scars with a high-energy, pulsed carbon dioxide laser. Dermatol Surg 22 151-154... 

Optically-pumped lasers (OPLs) offer very useful power levels at discrete frequencies well into the THz band. Most OPLs comprise some sort of gas cell, which is the active laser medium, that is pumped by a carbon dioxide laser. These devices are inherently inefficient because the... 

Carbon dioxide lasers, 77 372 Carbon dioxide removal, molecular sieves in, 76 840... 

Kreuzer, L. B., N. D. Kenyon, and C. K. N. Patel. Air pollution Sensitive detection of ten pollutant gases by carbon monoxide and carbon dioxide lasers. Science 177 347-349. 1972. 

Helium [7440-59-7] - [MAGNESIUMAND MAGNESIUM ALLOYS] (Vol 15) -m carbon dioxide lasers [LASERS] (Vol 15) -as semiconductor bulk gases [HIGH PURITY GASES] (Supplement)... 

Waierbury. R.C. Catalysis Enable Sealed Carbon Dioxide Laser. Instnunentnumt lei hnnfityr, 80 i April 1990). 

Ignition Parameters B.N. Kondrikov et al, Ignition and Gasification of Ballistite Powder Under the Effect of Carbon Dioxide Laser Radiation , TrMoskKhimTekhnolInst 83, 67—78 (1974) (Russ) CA 85, 162865 (1976) [Reported is the effect of C02—laser radiation... 

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