| 摘要 |
PROBLEM TO BE SOLVED: To approximate a wavelength to 248 nm, to obtain high output, to eliminate toxicity and to enhance resolution performance by obtaining an output laser beam of a specific wavelength from two laser beams. SOLUTION: A first laser beam source 1 consisting of respectively Q switch solid-state lasers is an Nd:YAG solid-state laser which generates the first laser beam of a wavelengthλ1 (=946 nm). A second laser beam source 2 is an Nd: YLF solid-state laser which generates the second laser beam of a wavelengthλ2 (=1047 nm). The first and second laser beams are made the same in the respective optical axes by using a dichroic mirror 3. The first and second laser beams are made incident on a sum frequency generator(SFG) 4, by which the laser beams are converted to the laser beam of a wavelengthλ3 =λ1.λ2/(λ+λ2)}. The wavelengthλ3 turns to about 497 nm. This laser beam is subjected to wavelength conversion to an output laser beamλ4 ofλ4[=λ3/2=λ1.λ2/ 2(λ1+λ2)} in wavelength. This wavelengthλ4 turns to about 248.5 nm.
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