High-efficiency X-ray multilayer-coated blazed gratings with shifted boundaries

Area of Science:

• Optics and Photonics
• Materials Science
• X-ray Optics

Background:

• Multilayer-coated blazed gratings are crucial components in X-ray optics.
• Current grating designs with conformal boundaries face limitations in production and efficiency.
• Achieving high diffraction efficiency is essential for advancing X-ray spectroscopy and imaging.

Purpose of the Study:

• To propose and investigate a novel design for high-efficiency multilayer-coated blazed X-ray gratings.
• To explore the impact of horizontal-shifted (non-conformal) boundary profiles on grating performance.
• To demonstrate the potential for improved diffraction efficiency using realistic, simulated boundary profiles.

Main Methods:

• Utilizing an integrated approach combining rigorous numerical calculations of light diffraction.
• Simulating multilayer grating growth to obtain realistic boundary profiles.
• Varying the incidence angle of the deposition flux to control boundary profile shifts.

Main Results:

• Shifted boundary profiles lead to substantially higher diffraction efficiency than conformal boundaries.
• High-efficiency gratings with shifted boundaries are achievable with specific deposition angles, favoring blaze facet coating.
• Demonstrated maximum absolute efficiencies of 23.3% (W/B4C) and 40.2% (Cr/C) with shifted boundary designs.

Conclusions:

• The proposed design with shifted boundary profiles offers a significant improvement in X-ray grating efficiency.
• This approach overcomes production difficulties associated with conformal gratings.
• The findings pave the way for more efficient X-ray optical elements in scientific instrumentation.