High-performance optical retarders based on all-dielectric immersion nanogratings

High-performance true zero-order optical retarders were realized based on all-dielectric immersion nanogratings. All-dielectric nanolaminate materials, deposited by atomic layer deposition, were utilized to fill the trenches of the nanogratings to form immersion nanogratings. The refractive index of the nanolaminate material can be dialed and controlled precisely by controlling the ratio of the two compositions forming the nanolaminate material. This significantly improves the design and process windows for realizing precise optical retarders, particularly very-low-phase retarders. Three 100-mm-diameter very-low-phase retarders with highly precise and uniform phase retardance and very high transmittance were realized by use of the all-dielectric immersion grating design and an atomic layer deposition technique.