Inverse design of high-NA metalens for maskless lithography
Haejun Chung1,2, Feng Zhang3, Hao Li4
1Department of Electronic Engineering, Hanyang University, Seoul, 04763, South Korea.
Nanophotonics (Berlin, Germany)
|December 5, 2024
Summary
We developed an improved metalens for maskless lithography, achieving higher focusing efficiency than theoretical designs. This advancement could enable cost-effective, large-area nanofabrication for research and industry.
Area of Science:
- Optics and Photonics
- Nanotechnology
- Materials Science
Background:
- Maskless lithography techniques like zone-plate-array lithography (ZPAL) are crucial for nanoscale research and industry.
- Improving the efficiency and cost-effectiveness of nanofabrication methods is an ongoing challenge.
Purpose of the Study:
- To design and demonstrate an axisymmetric inverse-designed metalens to enhance the performance of ZPAL.
- To establish a computational upper bound for unit-cell-based axisymmetric metalenses.
Main Methods:
- Derivation of a computational upper bound for unit-cell-based axisymmetric metalenses.
- Inverse design of a metalens optimized for high transmission and focusing efficiency.
- Fabrication and experimental validation of the designed metalens using electron beam lithography.
Main Results:
- Demonstrated a fabrication-compatible inverse-designed metalens with 85.50% transmission normalized focusing efficiency at 0.6 numerical aperture and 405 nm wavelength.
- Achieved higher efficiency compared to a theoretical gradient index lens design (79.98%).
- Experimental validation confirmed the performance of the axisymmetric inverse-designed metalens.
Conclusions:
- The developed axisymmetric inverse-designed metalens significantly improves upon existing theoretical designs for ZPAL.
- Metalens-based maskless lithography presents a promising pathway towards low-cost, large-area nanofabrication.
- This technology has the potential to advance nanoscale research and industrial applications.
