| 摘要 |
PROBLEM TO BE SOLVED: To obtain a super narrow band width laser device which can narrow the band of the laser beam from a fluorine laser or a laser, having a wavelength shorter than the fluorine laser has by using a diffraction grating as a band- narrowing element. SOLUTION: A laser resonator is constituted of a total reflection mirror 10 and a mirror 11. A diffraction grating 13 is set up at an incident angle of 80 deg. or larger so that the grating 13 functions an oblique-incident diffraction grating. In the grating 13, undo diffraction and reflection are produced, and the diffracted laser beam returns to the grating 13, after being reflected by the mirror 11. The reflected laser beam L10, however, is made incident to a prism 14. Since the grating 13 is of the oblique-incidence type, although the grating 13 and mirror 11 function as an output mirror, having high transmittance though the diffraction efficiency of the grating 13 being as low as 10-20%, because the grating 13 is applied on a fluorine (F2) laser or argon dimer (F2) laser. |
