Simulation of hard X-ray focusing using an array of cylindrical micro-holes in a diamond film

The focusing of hard x-rays was numerically simulated using a beam propagation method implemented in the BeamPROP software package and a Rayleigh-Sommerfeld integral. It was shown that when focusing hard X-rays of wavelength 1.34 A with sequentially arranged circular cylindrical microlenses (shaped as 10-µm micro-holes) found in a polycrystalline diamond film, a nearly 10 times shorter focal length of the microlens array can be achieved, reducing from 14.4 cm to 15 mm, via increasing the number of microlenses from 1 to 20. Meanwhile, the x-ray focal spot size was found to decrease 7 times along the minor axis from 1.5 μm to 200 nm, while the maximum intensity in the focus experienced a 40-times increase.