A new knife edge method is proposed to evaluate the density distribution of laser power converted by a kaleidoscope for CO2 laser processing. The density distribution of the laser power converted by the kaleidoscope and exposed on the calorimeter are calculated first. The power density distribution has a periodical pattern in the radial direction, which forms rings of equal density corresponding to the number of reflections of the laser against the inner surface of the kaleidoscope. The pattern of the power distribution obtained by the knife edge method proposed is in good agreement with the calculated one. It is concluded that the power density distribution measured agrees with the calculated one in quantity by introducing the from error coefficient in calculation to take account of the power loss at the time of reflection.
