| 摘要 |
PROBLEM TO BE SOLVED: To exactly adjust the laser wavelength by comprising a wavelength tuning device, having a turning range adequately to adjust the laser for operating at the wavelength of an absorption line for calibrating a wave meter. SOLUTION: A laser 30 is adjustable so as to function even at any wavelength in an ArF broadband spectrum, using a tuning mirror 36 in a line band- narrowed module 31, and adjusted by a pivot mirror 36 having a stepper mirror 39 so that a laser beam slightly changes the angle of incidence on a grading 38, a sufficient step with a stepper motor causes a change of about 0.15 pm a the nominal narrow-band output center wavelength, and a stepper motor scan of 2-3 mm can adjust precisely the laser wavelength in the narrow tuning range adequate for scanning the output wavelength of the laser 30 via 500 pm in a tuning range from about 193,100 pm to about 193,600 pm. |
