Maxim Polikarpov

Large-acceptance diamond planar refractive lenses manufactured by laser cutting

For the first time, single-crystal diamond planar refractive lenses have been fabricated by laser micromachining in 300 µm-thick diamond plates which were grown by chemical vapour deposition. Linear lenses with apertures up to 1 mm and parabola apex radii up to 500 µm were manufactured and tested at the ESRF ID06 beamline. The large acceptance of these lenses allows them to be used as beam-conditioning elements. Owing to the unsurpassed thermal properties of single-crystal diamond, these lenses should be suitable to withstand the extreme flux densities expected at the planned fourth-generation X-ray sources.

Parabolic single-crystal diamond lenses for coherent x-ray imaging

We demonstrate parabolic single-crystal diamond compound refractive lenses designed for coherent x-ray imaging resilient to extreme thermal and radiation loading expected from next generation light sources. To ensure the preservation of coherence and resilience, the lenses are manufactured from the highest-quality single-crystalline synthetic diamond material grown by a high-pressure high-temperature technique. Picosecond laser milling is applied to machine lenses to parabolic shapes with a ≃1 μm precision and surface roughness. A compound refractive lens comprised of six lenses with a radius of curvature R=200 μm at the vertex of the parabola and a geometrical aperture A=900 μm focuses 10 keV x-ray photons from an undulator source at the Advanced Photon Source facility to a focal spot size of ≃20×90 μm2 with a gain factor of ≃50−100.

X-ray harmonics rejection on third-generation synchrotron sources using compound refractive lenses.

A new method of harmonics rejection based on X-ray refractive optics has been proposed. Taking into account the fact that the focal distance of the refractive lens is energy-dependent, the use of an off-axis illumination of the lens immediately leads to spatial separation of the energy spectrum by focusing the fundamental harmonic at the focal point and suppressing the unfocused high-energy radiation with a screen absorber or slit. The experiment was performed at the ESRF ID06 beamline in the in-line geometry using an X-ray transfocator with compound refractive lenses. Using this technique the presence of the third harmonic has been reduced to 10(-3). In total, our method enabled suppression of all higher-order harmonics to five orders of magnitude using monochromator detuning. The method is well suited to third-generation synchrotron radiation sources and is very promising for the future ultimate storage rings.

Linear parabolic single-crystal diamond refractive lenses for synchrotron X-ray sources

Linear parabolic diamond refractive lenses are presented, designed to withstand high thermal and radiation loads coming from upgraded accelerator X-ray sources. Lenses were manufactured by picosecond laser treatment of a high-quality single-crystal synthetic diamond. Twelve lenses with radius of curvature at parabola apex R = 200 µm, geometrical aperture A = 900 µm and length L = 1.5 mm were stacked as a compound refractive lens and tested at the ESRF ID06 beamline. A focal spot of size 2.2 µm and a gain of 20 were measured at 8 keV. The lens profile and surface quality were estimated by grating interferometry and X-ray radiography. In addition, the influence of X-ray glitches on the focusing properties of the compound refractive lens were studied.

Polymer X-ray refractive nano-lenses fabricated by additive technology

The present work demonstrates the potential applicability of additive manufacturing to X-Ray refractive nano-lenses. A compound refractive lens with a radius of 5 µm was produced by the two-photon polymerization induced lithography. It was successfully tested at the X-ray microfocus laboratory source and a focal spot of 5 μm was measured. An amorphous nature of polymer material combined with the potential of additive technologies may result in a significantly enhanced focusing performance compared to the best examples of modern X-ray compound refractive lenses.

Laboratory and synchrotron tests of two-dimensional parabolic x-ray compound refractive lens made of single-crystal diamond

2D parabolic X-ray compound refractive lens was manufactured by laser micro-machining of a single-crystal diamond. The lens consists of parabolic half lenses with apertures of 1 mm and parabola apex radii of 200 μm. It has been tested at the synchrotron undulator source (ID06, ESRF) and at a laboratory setup using MetalJet X-ray tube with a liquid-gallium jet as the anode. X-ray imaging and focusing modes were used. Unique optical and thermal properties of singlecrystalline diamond lenses allow them to be applied as focusing, imaging and beam-conditioning elements at high-heat flux beams of today and future X-ray sources.

Focusing of white synchrotron radiation using large-acceptance cylindrical refractive lenses made of single – crystal diamond

Large-aperture cylindrical refractive lenses were manufactured by laser cutting of single-crystal diamond. Five linear single lenses with apertures of 1mm and the depth of the structure of 1.2 mm were fabricated and tested at the ESRF ID06 beamline performing the focusing of white-beam synchrotron radiation. Uniform linear focus was stable during hours of exposure, representing such lenses as pre-focusing and collimating devices suitable for the front-end sections of today synchrotron radiation sources.

Diamond x-ray refractive lenses produced by femto-second laser ablation

Femto-second laser processing of polycrystalline CVD diamond was applied to manufacturing of X-ray planar refractive lenses. Surface morphology and material quality were analyzed with optical and scanning electron microscopy and X-ray radiography. Lenses were tested in a focusing mode at the IIIrd generation synchrotron radiation source (ESRF).

Imaging by 2D parabolic diamond X-ray compound refractive lens at the laboratory source

Laser micro-machining of single-crystal diamond was successfully applied to the manufacturing of a 2D parabolic X-ray compound refractive lens which consists of 24 plano-concave lenses with the parabola apex radius of 200 µm and the aperture of 1 mm. It was tested in the image transfer mode of the tungsten resolution test target at the original home-lab setup using Cukα radiation from a Rigaku rotating anode X-ray generator. The high quality transfer X-ray imaging of this target with resolution < 20  µm in the field of view of 0.6 mm was demonstrated with use of the parabolic diamond compound refractive lens.

X-ray harmonics suppression by compound refractive lenses

X-ray refractive lenses were successfully applied to harmonics rejection by using the fact that focal distance of the lens is energy-dependent. Spatial separation of energy spectrum by focusing the fundamental harmonic at the focal point and suppressing the unfocused high-energy radiation with a screen absorber or slit was achieved by usage of an off-axis illumination of refractive lenses at the ESRF ID06 beam-line. The presence of the 3rd harmonic has been reduced down to 10-3 using this technique and down to 10-5 by additionally using of monochromator detuning. The method is well suited to third-generation synchrotron radiation sources and very promising at the future ultimate storage rings.