摘要
Dual-beam interference lithography is a core technology for two-dimensional(2D)grating fabrication.However,significant morphological deviations occur between the fabricated structures and traditional theoretical models,causing diffraction efficiency prediction discrepancies.To address this issue,this paper proposes a hole–pillar coupled design model for 2D gratings fabricated via dual-beam interference lithography.By constructing the actual three-dimensional(3D)grating morphology,the proposed model describes the grating profile evolution during fabrication accurately.Using an inverse grating design method based on the Fourier modal method,a polarization-independent 2D grating structure with high diffraction efficiency was optimized for a 670 nm working wavelength.A 2D grating with a line density of 1200 gr/mm was fabricated using dual-beam interference lithography.Experimental results show that,when transverse electric/transverse magnetic-polarized light at 670 nm is perpendicularly incident,the diffraction efficiency of the(±1,0)and(0,±1)orders exceeds 20%,with a polarization imbalance of less than 3%.Atomic force microscopy characterization reveals a correlation coefficient of 0.988 between the actual and designed grating structures,verifying the proposed model's accuracy.The model provides a precise description of the groove profile in 2D holographic gratings,expands the grating fabrication tolerance,and provides a theoretical foundation for the development of next-generation nanoscale-precision multi-degree-of-freedom measurement systems.
基金
Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022218)
Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0280101)
National Natural Science Foundation of China(62435019)
CAS Project for Young Scientists in Basic Research(YSBR-103)
National Key Research and Development Program of China(2023YFF0715802)
Jilin Province and Chinese Academy of Sciences Science and Technology Cooperation High-Tech Industrialization Special Program(2024SYHZ0018)。
