| 摘要 |
PURPOSE:To excellently stabilize wavelength of laser beam by fixedly maintaining distribution of an intensity ratio or the like of the main wavelength to secondary wavelength of a wavelength spectrum of the narrow-banded laser beam. CONSTITUTION:Narrow-banded laser beam is oscillated and output in a resonator consisting of a laser oscillation part 12, a front mirror 14, a rear mirror 16 and etalon 18. Oscillated laser beam is partially taken out of detection in a partial mirror 26 and this taken-out laser beam penetrates an etalon 28 for monitoring and a lens 30 to be incident upon a detector 32. Next, detection of the spectra generated respectively corresponding to three kinds of wavelength of the main wavelength and two kinds of secondary wavelength to be obtained in the etalon 18 is performed in the detector 32 and three spectra of the central wave numbers K-1, K0 and K1 are observed as shown by a solid line. And, when both intervals of the etalon 18 are so controlled as to maintain a ratio of the intensity of the number of waves K0 of the main wavelength to the intensity of light of the number of waves K1 or K-1 of the secondary wavelength constant, the main wavelength, that is the whole wavelength can be stabilized. |
