Computing X-Ray Reflectance of Focusing Multilayer Films

Dwight W. Berreman

doi:10.1117/12.949664

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6 May 1985 Computing X-Ray Reflectance of Focusing Multilayer Films

Dwight W. Berreman

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Proceedings Volume 0563, Applications of Thin Film Multilayered Structures to Figured X-Ray Optics; (1985) https://doi.org/10.1117/12.949664
Event: 29th Annual Technical Symposium, 1985, San Diego, United States

Abstract

F. Abeles developed an exact 2X2 matrix method for computing reflectance and transmittance of flat stratified structures of arbitrary complex refractive index profile. By distorting the coordinate system for his method from rectagular to confocal ellipsoids of revolution, the same method can be applied to focusing systems. The well-known 1:1 toroidal focusing geometry occurs at the equators of the ellipsoids. Near the equator, if the Bragg angle is not too small, and also close to the axis of foci, curved layers of uniform thickness are often close enough to the ideal profile for satisfactory spatial and spectral resolution. In very thick multilayers with small absorption, uniform layer thickness in the toroidal geometry results in some dispersion with PendellOsung fringes. Away from the equator or axis, and particularly at low Bragg angles, profiling or gradation of thickness may be necessary for satisfactory resolution. Examples of computations with Abeles's method are shown.

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Dwight W. Berreman "Computing X-Ray Reflectance of Focusing Multilayer Films", Proc. SPIE 0563, Applications of Thin Film Multilayered Structures to Figured X-Ray Optics, (6 May 1985); https://doi.org/10.1117/12.949664

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