Patent Number: 
Section: claims

1. An X-ray waveguide, comprising:a core for guiding an X-ray; anda cladding for confining the X-ray in the core,wherein:the cladding has a one-dimensional periodic structure containing materials having different real parts of refractive index;the materials include one of an organic material, a gas, and a vacuum, and an inorganic material; andthe core and the cladding are formed so that a critical angle for total reflection at an interface between the core and the cladding is smaller than a Bragg angle depending on a periodicity of the one-dimensional periodic structure. 2. The X-ray waveguide according to claim 1, wherein:the one-dimensional periodic structure contains a mesoporous material having a one-dimensional periodicity in a direction perpendicular to the interface between the cladding and the core; andthe mesoporous material is perforated with pores that elongate in a guiding direction of X-ray. 3. The X-ray waveguide according to claim 1, wherein the inorganic material comprises an oxide. 4. The X-ray waveguide according to claim 1, wherein the one-dimensional periodic structure includes a mesostructured film of lamellar structure. 5. The X-ray waveguide according to claim 1, wherein the number of periods of the one-dimensional periodic structure is 20 or more.