Large area nanoimprint enables ultra-precise x-ray diffraction gratings.

Area of Science:

• Optics and Spectroscopy
• Materials Science and Engineering
• Nanotechnology

Background:

• High-resolution X-ray spectroscopy demands diffraction gratings with exceptional precision.
• Existing fabrication methods face challenges in achieving nanometer-scale groove accuracy over large areas.
• The development of advanced gratings is crucial for enhancing spectroscopic capabilities.

Purpose of the Study:

• To develop a novel fabrication process for ultra-precise diffraction gratings.
• To achieve nanometer-scale accuracy in groove placement for constant or variable line spacing (VLS) gratings.
• To demonstrate the efficacy of the developed process for soft X-ray spectroscopy.

Main Methods:

• Utilizing electron-beam (e-beam) lithography to record grating patterns on quartz plates with nanometer-scale groove placement accuracy.
• Employing large-area nanoimprint lithography to transfer the grating pattern to a massive grating blank.
• Applying dry and/or wet etching techniques for precise groove shaping.
• Confirming the fidelity of the nanoimprint transfer using differential wavefront measurements.

Main Results:

• Successfully fabricated a lamellar 900 lines/mm VLS grating.
• Demonstrated nanometer-scale accuracy in groove placement throughout the fabrication process.
• Verified high fidelity of the nanoimprint transfer step through wavefront measurements.
• The developed process is suitable for creating gratings for soft X-ray fluorescence spectrometers.

Conclusions:

• The developed fabrication process enables the production of ultra-precise diffraction gratings.
• The combination of e-beam lithography and nanoimprint lithography offers a viable route for high-accuracy grating fabrication.
• The fabricated VLS grating is suitable for advanced spectroscopic applications, such as soft X-ray fluorescence spectroscopy.