Compact waveguide carbon dioxide array lasers and beam reformatting techniques for laser surface treatment applications

A 2 kW waveguide carbon dioxide (CO₂) laser array arranged in a compact 16×4 matrix is described. Each channel, of dimensions 2.25×2.25×590 mm, produces a near-perfect EH₁₁ waveguide mode beam with a propagation distance before the onset of overlap of 250 mm. The 2 kW 16×4 two-dimensional (2-D) array produces an output beam of cross section approximately 50×40 mm in the near field. The laser head has external dimensions of 1000×200×200 mm. In addition, a compact and portable 7×1 element linear array producing an output of 100 W has been constructed for array reformatting and related experiments. The 7 individual 2.25×2.25×37 mm waveguides produce a 100 W output beam of cross section approximately 2.25×20 mm in the near field. The laser head has external dimensions of length 570 mm and diameter 100 mm. Both laser systems operate sealed-off. The results of close-packing the output from the two waveguide CO₂ lasers using two separate beam reformatting techniques are presented. A modified version of the two-mirror Clarkson-Hanna arrangement, placed inside the laser, vacuum chamber, reformats the 4×16 matrix into an 8×8 close packed array, increasing the fill factor and brightness of the array both by a factor of two. Diffractive optical elements (DOEs) are employed to reformat the 7×1 array laser into a close-packed hexagon, 2+3+2, array.