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 ion-etched blazed grating substrate that had 2400 grooves/mm and a radius of curvature of 2.2 m. Scanning probe microscopy yielded the same surface microroughness (5 Angstrom rms) before and after deposition of the multilayer. The efficiency and polarization performance of the grating was measured by synchrotron radiation in the 135-250-Angstrom wavelength 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 performance 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 optical element in the wavelength bands between 125 and 300 Angstrom, which are covered by the multilayer coating. (C) 1995 Optical Society of America