Determination of the refractive index at soft X-ray resonances

Abstract

The dispersive part of the refractive index, 1 - δ, of vanadium is determined by measuring the angular dependence of the Bragg peak at the V L 2,3 edge energy region using a Fe/V superlattice. This X-ray scattering technique provides access to the direct determination of the dispersive part of the refractive index across an absorption resonance and to the change of values from below unity to above unity. We demonstrate that previously tabulated values tend to underestimate the amplitude of the change in the real part of the refractive index. We also examine the need for applying absorption and polarization corrections. © 2004 Elsevier B.V. All rights reserved.