PROPAGATION OF A LASER BEAM THROUGH ATMOSPHERE - A DESIGN CONSIDERATION FOR LASER BEAM MACHINE.

When a high power CO//2 CW laser beam is propagated through the atmosphere, the design of the air under irradiation changes. This will cause distortion of the laser beam. Also, due to the infrared radiation, the optical system of the laser absorbs some fraction of the incident laser beam and change their shapes consequent distort the laser beam. This paper examines the propagation of CO//2 CW laser beam through the atmosphere and via the focusing lens to the workpiece. The absorption and heating effects of atmosphere on the laser beam is determined by the use of the Fast Fourier Transforms method. It is found that the overall reduction in intensity by the adsorption of irradiated air is about 4. 8%, which is consistent with the Frootan results.