| 摘要 |
PURPOSE:To obtain a laser output having stable narrowed spectral width, to reduce a special coherence and to eliminate a speckle in case of a lithography by forming the laser medium of a main oscillator of a slablike solid material, forming the sectional shape of an oscillated laser light in an optical axis direction in a slit state, and exciting and amplifying it as it is. CONSTITUTION:A main oscillator 17 has a slablike alexandrite 19 as a laser medium and a pair of Xe lamps 20, 21 oppositely provided on the opposite surface parts of the alexandrite 19. An optically pumping light source driver 22 controls the light emission of the lamps 20, 21. First slit plate 25 and a prism beam expander 26 are sequentially provided between a diffraction grating 23 and the alexandrite 19. First and second slit plates 25, 28 are formed with slits 25a, 28a passed continuously laterally. A laser light emitted from the mirror 24 of the oscillator 17 is incident to an amplifier 18. |
