X-RAY FILTER USING MULTILAYERS WITH MODULATED REFRACTIVE-INDEX

We have numerically computed the reflectivity of X-rays incident norma lly onto metallic multilayers. The structure consists of two alternati ng types of constituent layers. One type has the same refractive index whereas the refractive index of the other type is modulated by a Gaus sian function along the normal direction. We have found that the refle ctivity of the structure becomes unity in a wide range of wavelengths. The bandwidth of the reflection can be finely tuned by varying the wi dth of the Gaussian function. (C) 1998 Published by Elsevier Science B .V.