US Patent 11550083 Techniques for manufacturing slanted structures

A surface-relief grating comprises a plurality of grating ridges including a first material, and a layer of a second material conformally deposited on surfaces of the plurality of grating ridges. A first region of the surface-relief grating is characterized by a first grating depth and a first duty cycle greater than a first threshold value. A second region of the surface-relief grating is characterized by a second grating depth and a second duty cycle lower than a second threshold value that is lower than the first threshold value. A difference between the first grating depth and the second grating depth is less than 20% of the second grating depth.