Ignition of Solid Combustibles by a Ruby Laser

摘要

The ignition of solid combustibles with a 3 millisecond pulse ruby laser has been performed. The samples investigated are newspaper, alpha cellulose, kraft paper, cotton, clothing, grass and wood. The samples studied were categorized according to their reflectances and absorptances at a wavelength of 6943A. The threshold energy for sustained ignition is reported as joules per unit area delivered to the surface of the material. The results of these experiments show that sustained ignitions depend upon the area exposed to the laser beam, the reflectance of the surface in the case of newspaper samples, and the thickness of the material. Wood shingles and cloth were only damaged; carbon impregnated alpha cellulose thicker than 8 mils and newspaper samples thicker than 19 mils did not burn. (Author)