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Christiansen, W. H.

Works: 8 works in 12 publications in 1 language and 151 library holdings
Roles: Author
Classifications: TL557.F6, 551.6875
Publication Timeline
Publications about W. H Christiansen
Publications by W. H Christiansen
Most widely held works by W. H Christiansen
Studies of blackbody-pumped lasers semi-annual progress report, January 1, 1988 - June 30, 1988 by W. H Christiansen( Book )
1 edition published in 1988 in English and held by 71 libraries worldwide
Scaling studies of solar pumped lasers semi-annual progress report, January 1, 1985-June 30, 1985 by W. H Christiansen( Book )
1 edition published in 1985 in English and held by 69 libraries worldwide
A study of fog clearing using a CO2̳ laser by G. J Mullaney( Book )
3 editions published in 1969 in English and held by 3 libraries worldwide
It has been suggested that haze and fog may be dissipated by using a 10.6 micron laser beam. This radiation is strongly absorbed by liquid water but only weakly absorbed by water vapor. Thus, the laser selectively deposits its energy in the water droplet, ultimately evaporating it. In this paper, the physics of fog removal by a CO2 laser is explored and the possibility of clearing airport runways is evaluated. While initial estimates of the power required to clear a runway are large for present-day laser devices, they may not be excessive requirements for future systems. (Author)
A Fluid-Mechanical Refracting Gas-Prism ( Book )
3 editions published between 1971 and 1979 in English and held by 3 libraries worldwide
In many high power laser systems, the interaction of either electromagnetic radiation or an electric discharge with a flow system has proved an important phenomenon. Knowledge of the interaction of laser radiation and flow is required to understand the performance of aerodynamic windows and the nonlinear effects of thermal blooming, which involves significant effects caused by small energy losses of the beam. The small losses usually associated with simple refraction of light in gases may be useful and have motivated us to develop and study a unique fluid mechanical device for possible manipulation and storage of laser radiation. A low power beam of light can be deflected continuously through large angles along a curved path using the flow from a convergent-divergent nozzle sector whose throat lies on an arc of a circle. The flow devices that have been built and studied, based on this concept, have been dubbed Venus machines because of the similarity to the optical conditions predicted to exist in the atmosphere of Venus. New and more accurate transmission data is presented wherein transmission measurements in excess of 99.5% are detailed. This data permits detailed analysis of the light well and a more accurate assessment of the optimum operating conditions of the Venus Machine. (jhd)
1 edition published in 1968 in English and held by 2 libraries worldwide
Laboratory measurements have been made of the evaporation rate of fog when subjected to an intensity of 5 to 50 W/sq cm of 10.6/microns radiation. The measurements agree with calculations and show that most of the absorbed laser energy goes into heating the air by conduction from the droplet surface. This heated air induces a motion which prevents the laser from completely clearing the fog. A correlation is found which describes the visibility improvement as the fog and power density are varied. (Author)
Experimental Studies of Laser Beam Degradation by Turbulent Shear Layers ( Book )
1 edition published in 1991 in English and held by 1 library worldwide
The degradation of a laser beam by turbulent shear layers has been systematically and experimentally studied with variation in parameters. The near-field measurement results showed that the growth rates of the shear layers decreased drastically with increase in Mach number and were dependent, to a lesser extent, on the density ratio. The optical far-field measurements results showed that the Strehl ratio decreased with increase in refractive index change across the shear layers, with increase in growth, with increase in downstream distance of the nozzle exit, and with increase in beam diameter
Research on the Flow Phenomena Related to High Power Laser ( Book )
1 edition published in 1982 in English and held by 1 library worldwide
The fundamental mechanisms of the interaction of electrical discharges of the glow type and the fluid mechanics normally found in electric discharge lasers have been studied in an effort to improve their performance capability. Basic information on these devices was obtained via small-scale experiments at the University of Washington. An alternative method of phase compensation for laser beams using the refractive properties of gas jets was also investigated. The amount of beam degradation produced by turbulent shear layers in the jets was studied also. The experimental investigation of this beam degradation mechanism constitutes much of the effort in the project. Theoretical calculations detailing the effects of mixing of dissimilar gases at low Mach number have been carried out. High-power laser mixing flows have been studied by numerical, analytical, and experimental techniques. The models for wave decay in supersonic cavity flows have been extended, optical sensitivities calculated, and experiments conducted using a laser interferometer. Calculated thermodynamic parameter history through decaying wave systems has been used with simple HF reaction models to study strongly-coupled reaction shocks. A systematic study of the sensitivity of HF laser performance to fluid process assumptions has been carried out, with emphasis on power extraction measurements from a versatile shock/Ludwieg tube laboratory laser. (Author)
1 edition published in 1969 in English and held by 1 library worldwide
The afterglow pulse-gain technique was used to measure the relaxation of the upper laser level in N2O from 300 to 700K. Measurements of the relaxation time at 300K agree with the fluorescence technique results of Yardley. Gain studies were also made with gas mixtures in a non-flow system. Singly pulsed N2O + CO + He mixtures at 300K showed considerable peak gain. However, subsequent pulses of these mixtures show that the gain is reduced because of the chemical reaction forming CO2. Measurements of this transformation from one molecular laser mixture to another are discussed. (Author)
English (12)
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