Large-acceptance diamond planar refractive lenses manufactured by laser cutting

Abstract

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.

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

“…Single lenses have being successfully focusing the white beam during several hours of exposure with no degradation of the focal spot size and gain. At the present research we amplified the depth of the lenses up to 1.2 mm in comparison with laser-cut 300 μm in [10], preserving the verticality of the lens' walls, seen from the uniformity of the focal line in the horizontal direction. Whereas the circular profile did not allow us to use the whole lens' aperture in vertical direction because of spherical aberrations, (transparent aperture A t is 376 microns as described earlier), parabolic one is free of such limitations while, technically, the principle of the parabolic lens' manufacturing is absolutely the same.…”

“…The scanning electron micrograph ( Fig. 1) shows improved quality of the lens side walls, namely its roughness and verticality, in comparison with the laser-cut lens in [10] where 'scallop'-like roughening of the surface caused by guidance during the cutting process was clearly seen at the parabola apex. Five single linear diamond lenses were stacked as the Compound Refractive Lens (CRL) [12] and tested at the ID06 beamline of the European Synchrotron Radiation Facility.…”

“…Concerning the optical properties, diamond is a low-Z material and has an absorption which is tenfold worse than that of beryllium, whereas the refractive index is double of the beryllium, cutting by a factor of two the number of X-ray lenses in the experimental scheme. Furthermore, the possibility of manufacturing of planar X-ray refractive lenses [9] with high acceptance by laser cutting of a single-crystal diamond [10] opens a door to their usage as 'front end' beam-conditioning optics. In the last case, single-crystal diamond preserves the spatial coherence of the radiation, adding no speckles.…”

Development of Hard X-ray Focusing Optics at Diamond Light Source

“…Finally, lens depth can be increased from the current 30-50 μm by longer deposition runs. Prototype laser-milled single crystal diamond lenses, with sub-mm acceptance, are being fabricated by several groups [10,11], but have yet not achieved micro-focusing. The availability of large diamond synthetic crystals, of high quality, is probably a few years in the future.…”

Single-crystal diamond refractive lens for focusing X-rays in two dimensions. Erratum

“…The correct citation should read Polikarpov et al (2015), and the reference is given in full in the list below.…”