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 mu m-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 mu m 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.