Polarized holographic lithography system for high-uniformity microscale patterning with periodic tunability

摘要

Periodic microscale array structures play an important role in diverse applications involving photonic crystals and diffraction gratings.A polarized holographic lithography system is proposed for patterning high-uniformity microscale two-dimensional crossed-grating structures with periodic tunability.Orthogonal two-axis Lloyd's mirror interference and polarization modulation produce three sub-beams,enabling the formation of two-dimensional crossed-g rating patterns with wavelength-comparable periods by a single exposure.The two-dimensional-pattern period can also be flexibly tuned by adjusting the interferometer spatial positioning.Polarization states of three sub-beams,defining the uniformity of the interference fringes,are modulated at their initial-polarization states based on a strict full polarization tracing model in a three-dimensional space.A polarization modulation model is established considering two conditions of eliminating the unexpected interference and providing the desired identical interference intensities.The proposed system is a promising approach for fabricating high-uniformity two-dimensional crossed gratings with a relatively large grating period range of 500-1500 nm.Moreover,our rapid and stable approach for patterning period-tunable two-dimensional-array microstructures with high uniformity could be applicable to other multibeam interference lithography techniques.