| 摘要 |
PROBLEM TO BE SOLVED: To obtain an illumination optical system which can improve the rotation symmetricity of an illuminating light, is small in size and facilitates maintenance. SOLUTION: A light branched from a laser beam, whose wavelength is within a range from a visible range to an infrared range and which is emitted from a DFB(distributed feedback) laser, etc., is amplified by a plurality of optical amplification units with optical fiber amplifiers in a fundamental wave generating unit 100 and is supplied to a wavelength conversion unit 20 via an optical fiver bundle 19. An illuminating light IL which is obtained by converting the supplied light into an ultraviolet light is divided into two by a polarization beam splitter 106A. The two divided beams are turned so as to have a rotational difference of 90 deg. between each other and combined with each other. The combined light is supplied to a fly-eye lens 110, and a reticle R is illuminated by the exposing light from the fly-eye lens 110. |
