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X-ray focusing optics, irrespective of the technology employed, require extremely high precision of both manufacturing and metrology, and also require in-use operational stability. As the x-ray beam is being transported to the experimental area, distortions due to misalignments, the imperfection of optics, and other effects will accumulate and result in beam quality degradation—spatial broadening, and the appearance of beam tails and aberrations.
Recently, it became possible, using ptychography methods, to quantify cumulative beam phase distortion. Based on these measurements, a single element of refractive optics, a phase correction plate, can be designed to correct for this cumulative beam degradation. Following successful experiment at LCLS [Seiboth, F. et al. Perfect X-ray focusing via fitting corrective glasses to aberrated optics. Nat. Commun. 8, 14623 doi: 10.1038/ncomms14623 (2017)], where phase plate was etched out of silica, Euclid Techlabs LLC uses femtosecond laser ablation to produce similar phase correctors out of diamond. In this paper we will present several examples along with measurements done at the Advanced Photon Source of Argonne.
This approach is plug and play, and can be employed in a large number of x-ray beamlines around the world. The ability to synthesize and rapidly produce a phase-correcting plate is a paradigm shift in the design of x-ray optics systems. Rather than require unprecedented fabrication tolerance, for example, for x-ray mirrors, while simultaneously managing thermal effects like non-uniform expansion due to the x-ray flux, one can focus on thermal stability while employing a simpler geometry, and use a complimentary phase plate that will correct the imperfections of the mirror. This technology will increase the quality of the x-ray beam and simplify beam delivery and alignment.
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