Annular lithography for fabricating micro- and mesoscale optical structures on curved surfaces

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Micro- and mesostructure fabrication is crucial for advanced optical and electronic devices.
• Current lithography techniques often face limitations when applied to curved surfaces.
• Annular lithography offers potential for novel patterning but requires specialized equipment.

Purpose of the Study:

• To present a novel exposure system for annular lithography.
• To enable the fabrication of micro- and mesostructures on curved surfaces for the first time.
• To demonstrate the system's capability in creating diffractive optical elements.

Main Methods:

• Utilized an axicon zoom system for ring generation.
• Incorporated a high numerical aperture optical design for enhanced resolution.
• Implemented telecentric imaging for constant ring diameter along the optical axis.
• Integrated an observation unit and autofocus system for precise control.

Main Results:

• Successfully fabricated micro- and mesostructures on both planar and curved (68.8 mm radius) substrates.
• Achieved narrow exposure ring widths of approximately 10 µm.
• Demonstrated structuring with feature periods ranging from 60 µm to 460 µm.
• Varied ring diameters from 400 µm to 8 mm.

Conclusions:

• The developed exposure system effectively enables annular lithography on curved surfaces.
• The system offers high resolution and precise control over patterned features.
• This advancement opens new possibilities for fabricating optical components on non-planar substrates.