| 摘要 |
PURPOSE:To obtain the profile accurate beam, by providing the 1st photodetector receiving laser light from nonoutput side of a laser resonator and the 2nd photodetector having a light shield plate having aperture scanned orthogonal to the optical path from the output side, and measuring the beam diameter with the ratio of the 2nd detector output to the 1st detector output. CONSTITUTION:The light from nonoutput side of a laser resonator 1 is detected at the 1st photodetector, and the output is fed to a division circuit 11 via an amplifier 9. On the other hand, a light shielding plate having an aperture 5 about 50mu in diameter is fixed to the 2nd photodetector 3 provided at the output side of the laser resonator 1. The 2nd photodetector is scanned toward the arrow A orthogonal to the optical path with a motor 6 via a rope 7 and a spring 8. The output is fed to the division circuit 11 via an amplifier 10. The time mark signal of a photocoupler 14 by a chopper fitted to the motor 6 is fed to an XY recorder 12, which displays accurate profile of laser light beam by using the signal of the ratio of the 2nd detector output from the divider 11 to the 1st detector output. |
