A new application for x-ray lithography: Fabrication of blazed diffractive optical elements with a deep phase profile

Use of x-ray lithography to produce blazed diffractive optical elements (DOEs) is described. Proposed method allows one to make highly efficient blazed DOE with a deep phase profile (ten wavelengths and more) using a single x-ray mask with a binary transmission pattern. Unlike the well-known multilevel DOEs, blazed ones do not involve fabrication and aligning of a set of masks. DOEs with a profile depth of 10 {mu}m and more and zone sizes down to 1 {mu}m can be obtained due to the short wavelength and high penetrability of x rays. The first experimental samples of blazed DOEs with a 10 {mu}m-height profile--lenses and gratings - were fabricated by x-ray lithography with synchrotron radiation using the x-ray masks, prepared in accordance with the pulse-width modulation algorithm. Diffraction efficiency for lenses was measured for white light: it is higher than 80% for the central part of the lenses (inside a 10 mm diameter) and about 60% for an area of 20 mm diameter