| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a laser device which is usable for a light source of an exposure device, allows the downsizing of the device and facilitate maintenance and to suppress the widening of wavelength width occurring in the non-linear effect of an optical element to be used. SOLUTION: After an incident laser beam LB 3 of about 1.5μm in wavelength is amplified by an optical fiber amplifier 22 of a first stage, the laser beam is amplified by an optical fiber amplifier 25 of a second stage and the laser beam after the amplification is converted to UV light by frequency conversion. A narrow band-filter 24A and an isolator IS 3 are arranged between the optical fiber amplifiers 22 and 25, by which ASE(amplified spontaneous emission) noise, etc., are decreased.</p> |
