Atomic layer deposition, a highly uniform and conformal deposition process, was utilized to fill trenches of various high aspect-ratio nano-grating structures. Dielectric (e.g., SiO2), metal (e.g., aluminum), and dielectric/metal (e.g., Au/SiO2) hybrid nano-gratings with a linewidth down to < 50 nm and an aspect ratio up to 14:1 (700 nm: 50 nm) were trench-filled with various materials particularly nano-laminate materials such as TiO2/SiO2 and SiO2/Al2O3. Various high-performance optical devices such as true-zero-order optical retarders (i.e., wave plates) and nanowire-grid polarizers were realized based on an UV-nanoimprint lithography process and the atomic layer deposition for trench fillings. Thanks to both unique material properties and nano-structure trench filling capability, the atomic layer deposition opens a path for innovative nano-structure based optical devices and integrated optical devices. (c) 2005 American Vacuum Society.