Contact-interference Hybrid lithography: Toward Scalable Fabrication of cross-scale periodic micro structure and demonstration on infrared micro polarizer array

Abstract

Subwavelength grating micro-polarizer arrays, as a type of focal plane division simultaneous detection method, are significantly advancing the development and practical application of polarization imaging technology. Based on the cross-scale, dual-period characteristics of the grating array, this paper proposes a fabrication method that combines laser interference lithography with contact lithography. This method constructs a complete single-layer micro-polarizer array photoresist pattern through a four-step lithography process. Compared to traditional point-by-point fabrication methods like EBL and FIB, the patterning time is reduced by 3 to 4 orders of magnitude. Additionally, by introducing a refractive index matching liquid and an alignment method based on substrate contours, the effects of gaps and splicing errors are minimized, resulting in high-quality photoresist patterns with splicing errors less than 1{\mu}m. Finally, a double-layer metal grating structure was obtained through pattern transfer. Performance tests show that the micro-polarizer array achieves a maximum transmittance of over 50% and an extinction ratio exceeding 15dB in the 3-15{\mu}m wavelength range. This exploration offers a low-cost, high-efficiency path for fabricating micro-polarizer arrays.