Ultra-low blaze angle gratings for synchrotron and free electron laser applications.

D L Voronov,E M Gullikson,H A Padmore

doi:10.1364/oe.26.022011

Abstract

We have developed a method for the manufacture of x-ray diffraction gratings with arbitrarily small blaze angles. These gratings are made by a process in which a high blaze angle grating made by anisotropic etching of Si (111) is subjected to planarization and reactive ion etching. Differential etching of the planarization medium and silicon ensures reduction of the blaze angle. Repeated application of this process leads to gratings of increasing perfection with an arbitrarily small blaze angle. This opens the way to highly efficient low line density gratings, to damage resistant gratings for ultra-high power applications such as free electron lasers, and for extension of the use of gratings into the hard x-ray energy range for dispersive spectroscopy.

Highlights

X-ray diffraction gratings are widely used at synchrotron facilities around the world
The monochromator of the Cosmic beamline at the Advanced Light Source designed for coherent scattering and microscopy experiments is equipped with 4 gratings of groove density of 100 and 300 lines/mm [3]
To address the challenges mentioned above we developed a two-stage process for making high quality gratings with low groove density and ultra-small blaze angles

Summary

Introduction

X-ray diffraction gratings are widely used at synchrotron facilities around the world. Owing to the difference in the sputter yield of the metal and Si under bombardment by high energy ions of a noble gas, the transferred grating has a reduced groove depth and a lower blaze angle.

Results

Conclusion