Reflective optics for sub-10nm hard X-ray focusing

Abstract

Nanofocused X-rays are indispensable because they can provide high spatial resolution and high sensitivity for X-ray nanoscopy/spectroscopy. A focusing system with reflective optics is one of the most promising methods for producing nanofocused X-rays due to its high efficiency and beams size. So, far we realize efficient hard X-ray focusing with a beam size of 25nm. Our next project is realization of sub-10nm hard X-ray focusing. Here, we describe the design of the graded multilayer mirror and evaluation method for hard X-ray focused beam.

Aberrations in curved x-ray multilayers

“…Each ray (arrows) is tangential to the caustic (underlying curve) at the point where the latter intersects with the line corresponding to the local grazing angle (broken lines). Full circles correspond to Y values obtained with a ray tracing computer program [16] at the University of Osaka, using the same parameter set. There is a reasonably good agreement with the curves calculated at the ESRF.…”

“…RML based focusing optics with a diffraction limit below 10 nm would be needed. So far, such devices are not available, but strong efforts are under way to develop the required technologies [16]. …”

“…Several theoretical studies, mainly numerical wave optical calculations, were published treating the cases of FZPs [10], CRLs [11], TRMs [12,13], and MLLs [14,15]. Advanced numerical ray tracing calculations have been applied to RMLs [16]. Alternatively, a purely analytical approach was proposed [17,18].…”

Hard X-Ray Focusing with Curved Reflective Multilayers

“…Work at the ESRF (France) concentrated on ML coated flat mirrors integrated into dynamical benders to approach the optimum curvature [32]. SPring-8 and the University of Osaka (Japan) developed deterministic polishing techniques [33] and differential deposition to obtain ultra precise surfaces and the required ML coatings [34]. KB focusing systems for X-rays, though mainly based on TRMs, are commercially available from various suppliers.…”

“…Several theoretical studies, mainly numerical wave optical calculations, were published treating the cases of FZPs [11], CRLs [12], TRMs [13,14], and MLLs [15,16]. Advanced numerical ray tracing calculations have been applied to RMLs [17,18]. Alternatively, a purely analytical approach was proposed [19,20].…”