Advanced low blaze angle x-ray gratings via nanoimprint replication and plasma etch

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Diffraction gratings are crucial optical components in X-ray spectroscopy.
• Achieving ultra-low blaze angles is challenging with traditional fabrication methods.
• Existing gratings often lack the required groove quality for high-performance X-ray applications.

Purpose of the Study:

• To develop a new fabrication method for ultra-low blaze angle diffraction gratings.
• To reduce the blaze angle of master gratings using nanoimprint replication and plasma etching.
• To improve the groove quality and performance of gratings for X-ray applications.

Main Methods:

• Fabrication of a master blazed grating using anisotropic wet etching of silicon.
• Nanoimprint replication of the master grating into a polymer on a quartz substrate.
• Second nanoimprint to transfer the pattern to a resist on a silicon substrate.
• Reactive ion etching to transfer the grating grooves into the silicon substrate, reducing groove depth.

Main Results:

• Successfully fabricated a 200 lines/mm blazed grating with an ultra-low blaze angle of 0.2°.
• Demonstrated a blaze angle reduction factor of 5 compared to the master grating.
• Preserved the planarity of the optical surface and improved grating groove quality.

Conclusions:

• The developed method enables efficient fabrication of ultra-low blaze angle diffraction gratings.
• The process offers high accuracy and reproducibility for X-ray optical components.
• This technique advances the performance capabilities of diffraction gratings in X-ray applications.