Highly efficient ultra-low blaze angle multilayer grating.
- Author(s): Voronov, DL;
- Park, S;
- Gullikson, EM;
- Salmassi, F;
- Padmore, HA
- et al.
Published Web Locationhttps://doi.org/10.1364/oe.424536
We have developed an advanced process for blaze angle reduction of x-ray gratings for the soft, tender, and EUV spectral ranges. The process is based on planarization of an anisotropically etched Si blazed grating followed by a chemically selective plasma etch. This provides a way to adjust the blaze angle to any lower value with high accuracy. Here we demonstrate the reduction of the blaze angle to an extremely low value of 0.04°±0.004°. For a 100 lines/mm grating with a Mo/Si multilayer coating, the grating exhibits diffraction efficiency of 58% in the 1st diffraction order at a wavelength of 13.3 nm. This technique will be applicable to a wide range of uses of high efficiency gratings for synchrotron sources, as well as for Free Electron Lasers (FEL).