Fifth-order intrinsic aberration and extrinsic aberration of soft x-ray multi-element orthogonal arrangement optical system with large aperture

Based on fifth-order intrinsic aberration theory of plane-symmetric optical system with one-dimension source, the fifth-order intrinsic aberration and extrinsic aberration calculation method of soft x-ray multi-element orthogonal arrangement optical system with large aperture is studied. Firstly, the fifth-order intrinsic aberration calculation expressions of multi-element orthogonal arrangement optical system are given, and then, the fifth-order extrinsic aberration calculation method for this kind of optical systems are discussed and their corresponding expressions are derived; secondly, the fifth-order defocus aberration caused by the meridional field of source is analyzed in detail. Finally, applying the fifth-order aberration expressions and ray-tracing software Shadow to calculate the ray spot diagrams on the image plane of two design examples of soft x-ray multi-element orthogonal arrangement optical system with large aperture, respectively; and comparing these calculation results using two methods in the above, and they shows that the aberration expressions derived have a satisfactory calculation accuracy. The analytical analysis of aberration is helpful in the design and optimization of this kind of optical systems.