POLARIZATION AND EFFICIENCY OF A CONCAVE MULTILAYER GRATING IN THE 135-250-ANGSTROM REGION AND IN NORMAL-INCIDENCE AND SEYA-NAMIOKA MOUNTS

A molybdenum/silicon multilayer coating was applied to a holographic i on-etched blazed grating substrate that had 2400 grooves/mm and a radi us of curvature of 2.2 m. Scanning probe microscopy yielded the same s urface microroughness (5 Angstrom rms) before and after deposition of the multilayer. The efficiency and polarization performance of the gra ting was measured by synchrotron radiation in the 135-250-Angstrom wav elength region. In the second grating order and the second Bragg order of the multilayer coating, the peak normal-incidence efficiency was 7 .5% at a wavelength of 147 Angstrom, representing a groove efficiency of 27%. At an angle of incidence of 35 degrees, the polarization perfo rmance of the grating was 95%-100% in the 210-250-Angstrom wavelength region. In a Seya-Namioka spectrometer mount at an angle of incidence of 30 degrees-40 degrees, the grating is a nearly perfect polarizing o ptical element in the wavelength bands between 125 and 300 Angstrom, w hich are covered by the multilayer coating. (C) 1995 Optical Society o f America