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Updated: Jun 3, 2026
08:48
Writing Bragg Gratings in Multicore Fibers
Published on: April 20, 2016
A 10,000 groove/mm multilayer coated grating for EUV spectroscopy.
D L Voronov1, E H Anderson, R Cambie
1Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. dlvoronov@lbl.gov
Optics Express
|April 1, 2011
Summary
Researchers developed near-atomically perfect silicon substrates for Blazed Multilayer Gratings (BMGs) to achieve ultra-high spectral resolution in EUV and soft X-ray ranges. High efficiencies were demonstrated, though atomic surface mobility posed constraints.
Area of Science:
- Optics and Photonics
- Materials Science
- X-ray Astronomy
Background:
- Ultra-high spectral resolution is crucial for EUV and soft X-ray spectroscopy.
- Blazed Multilayer Gratings (BMGs) are essential for achieving this resolution.
- Optimal grating design, including substrate perfection and coating properties, is key.
Purpose of the Study:
- To demonstrate the production of near-atomically perfect silicon substrates for BMGs.
- To evaluate the performance of Al/Zr multilayer coatings on these substrates.
- To understand the impact of atomic surface mobility on grating efficiency.
Main Methods:
- Fabrication of silicon substrates with ultra-high groove density (10,000 l/mm).
- Application of Al/Zr multilayer coatings.
- Measurement of grating absolute efficiency at various incidence angles.
- Cross-sectional Transmission Electron Microscopy (TEM) analysis.
Main Results:
- Achieved 1st order absolute efficiencies of 13% at 11° and 24.6% at 36° incidence.
- TEM revealed smoothing effects due to atomic surface mobility.
- Correlated smoothing with a reduction in peak diffraction efficiency.
Conclusions:
- High performance is achievable with BMGs on anisotropic etched Si substrates.
- Atomic surface mobility during coating deposition imposes constraints on peak diffraction efficiency.
- Further optimization requires managing surface mobility effects.
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