| 摘要 |
PURPOSE:To reduce a fluctuation in the output of a laser beam and to improve the quality of a laser processing by a method wherein a sound absorbing material is mounted on the inner wall of an external container covering a wind guiding part or the interior of the container is partitioned by a partition wall constituted of the sound absorbing material or an elastic material and moreover, the frequency of pressure pulsation is determined in such a way that the frequency is within a range of specified multiple of an acoustic resonance frequency inherent to these devices. CONSTITUTION:A frequency to beat a pressure pulsation is determined in such a way that the frequency is included within a range 0.8 to 1.2 times larger than a resonance frequency, which is determined according to the volume of a space 12a of a resonance container 10 excluding a porous sound absorbing material 11a in the container 10, the aperture area of a side hole 8, the length of a connecting duct 9 and the speed of sound of a gas laser medium. The container 10 absorbs the energy of a frequency component of pressure pulsation, which coincides with a resonance frequency determined by Helmholtz's resonance theorem, and the energy is made to dissipate by a friction loss in the hole 8 and at the connecting part 9. At this time, the residual amount which is short dissipation is absorbed by the material 11a adhered on the inner wall of the container. As a result, as the pressure pulsation is absorbed before being propagated to a laser resonator 1 and a periodical fluctuation in the pressure of a gas laser medium in the resonator 1 is eliminated, a discharge voltage is not fluctuated and the degree of variability of laser output is reduced. |
