By the spherical diffraction grating the convergence optical incident die spectrum device

摘要

PROBLEM TO BE SOLVED: To turn a defocus term and a frame term of an optical path equation to zero and also reduce an aberration term of higher order in an entire object wavelength region to an oblique incidence of a large aberration in a spectroscopic system used primarily in regions of ultraviolet rays, vacuum ultraviolet rays, soft X rays.;SOLUTION: The apparatus has a rotatable spherical diffraction grating 3, a convergent mirror 6 for bringing a convergent light 2 to the spherical diffraction grating 3 and a rotatable output slit 5 for detecting an output light from the spherical diffraction grating 3. A diffraction condition of an optical path equation at the spherical diffraction grating is defined by 1/k= SINβ(COSα+cosβ)/(SINαCOS2β+COS2αSINβ), 1/k'=SINα(COSα+ cosβ)/(SINαCOS2β+COS2αSINβ).;COPYRIGHT: (C)2000,JPO