| 摘要 |
PURPOSE:To reduce the power density of a central part by having a first beam expanding part which expands the diameter of incident laser beams and emits these laser beams and a peripheral part beam reducing part which reduces only the diameter of the laser beams in the peripheral part among the laser beams emitted from the beam expanding part. CONSTITUTION:The laser beams 6 of multimodes largely oscillated in the power density of the central part of the beams are expanded m-times in diameter in the beam expanding part 1 and are made incident on a reflection mirror block 2 when these beams are made incident on the beam expanding part 1. The laser beams 6a, 6c are expanded m-times in the diameter by the beam expanding part l and thereafter, the beams transmit the reflection mirror block 2 as they are and are made incident on the peripheral part beam reducing part 5. The laser beam 6a is expanded m-times in the diameter in the beam expanding part is then reflected by the incident side mirror 3 of the reflection mirror block 2 and is made incident on the peripheral part beam reducing part 5 after the beam is introduced to the peripheral part. The laser beams 6b, 6c are reduced to 1/n in their diameter in the peripheral part beam reducing part 5 and are emitted. |
