Patent ID: 6480275
Filing Date: 2002-11-12
Classification: G01J

Abstract:
A high resolution monochromator having a very narrow slit function and a relatively large spectral range, said monochromator comprising:A) an etalon optical unit configured to monitor a beam of narrow band ultraviolet light and to produce interference fringes, said etalon optical unit comprising: 1) a diffuser positioned to diffuse said light into a very large number of directions to produce a diffuse beam; 2) an etalon positioned in the path of said diffuse beam; 3) a first slit aperture; and 4) a lens unit positioned to collect light passing through said etalon and to focus a portion of the passing light through said first slit aperture, B) a grating monochromator unit comprising: 1) a collimating optical unit positioned to collect light passing through said first slit aperture, 2) a grating positioned in an approximately Littrow configuration to reflect said collimated light back through said collimating optical unit so that spectral components of reflected light are focused by said collimating optical unit at positions dependent on wavelength of said spectral components, 3) a second slit aperture, 4) a mirror positioned to reflect through said second slit aperture a portion of said light passing back through said collimating optic, and 5) a light monitor positioned to monitor light passing through said second slit aperture, wherein said first and said second slit apertures are both positioned to pass a very narrow band of light having approximately the same narrow wavelength range.