Patent Number: 
Section: claims

1. A device for determining a spectrum of electromagnetic waves of a source, comprising:at least one reflective zone plate and at least one position-resolving detector, wherein the reflective zone plate comprises a multitude of predefined wavelength-selective regions arranged next to one another and the position-resolving detector comprises a multitude of corresponding receiving sections,wherein the wavelength-selective regions each include a multitude of reflecting arched portions which exclusively extend across the respective wavelength-selective region, characterized in thatthe arched portions each form a part of an ellipse, wherein the arched portions extend along at least 10% of the circumference of the respective ellipse. 2. The device according to claim 1, wherein the multitude of wavelength-selective regions are arranged separately next to one another. 3. The device according to claim 1, wherein a multitude of identical wavelength-selective regions are arranged separately next to one another. 4. The device according to claim 1, wherein a central energy of at least one of the wavelength-selective regions differs by less than 10% from a central energy of a neighboring wavelength-selective region. 5. The device according to claim 4, wherein a central energy of a multitude of wavelength-selective regions differs by less than 1% from a central energy of the respective neighboring wavelength-selective region. 6. The device according to claim 5, wherein a central energy of each of the wavelength-selective regions differs by less than 1% from a central energy of the respective neighboring wavelength-selective region. 7. The device according to claim 1, wherein neighboring wavelength-selective regions are adjacent to one another. 8. The device according to claim 1, wherein the arched portions preferably comprise a planar top surface while grooves are provided between the arched portions. 9. The device according to claim 8, wherein a depth of the grooves between neighboring arched portions increases continuously in the direction towards the detector. 10. The device according to claim 1, wherein a distance of neighboring portions along a longitudinal extension of the portions from a first end of the neighboring portions to a second end of the neighboring portions changes continuously in accordance with the Fresnel relationship. 11. The device according to claim 1, wherein a distance of neighboring portions along an axis perpendicular to a longitudinal extension of the portions from an end of the zone plate facing away from the detector to an end of the zone plate facing the detector changes continuously in accordance with the Fresnel relationship. 12. The device according to claim 1, wherein the reflecting portions preferably comprise a curvature in accordance with a wavelength range to be measured and the geometric dimensions and distances of source, zone plate, and detector. 13. The device according to claim 1, wherein the detector is planar and/or the multitude of corresponding receiving sections are arranged along one line.