SYNTHETIC WIDE BANDPASS X-RAY POLARIZERS

A wide bandpass x-ray polarizer for photon energies near 8358 eV (L-II I absorption edge of erbium) has been grown using molecular beam epita xy. The results illustrate a general approach to preparing graded-latt ice diffracting optical components. The active optical element is an 8 -mu m-thick single crystal film of In0.51Ga0.49Sb grown on a GaAs (001 ) substrate. The alloy was chosen to ensure maximum linear polarizatio n for the (006) Bragg reflection at the target energy. The polarizer r eflectivity has a full width at half-maximum of 27 eV in a fixed geome try with an angle of 90 degrees between the incident and diffracted be ams. (C) 1997 American Institute of Physics.