Modulation of rolling k vectors of angled gratings
Embodiments described herein relate to methods and apparatus for forming gratings having a plurality of fins with different slant angles on a substrate and forming fins with different slant angles on successive substrates using angled etch systems and/or an optical device. The methods include positioning portions of substrates retained on a platen in a path of an ion beam. The substrates have a grating material disposed thereon. The ion beam is configured to contact the grating material at an ion beam angle ϑ relative to a surface normal of the substrates and form gratings in the grating material.
1. A device comprising:
A substrate having a discrete input coupling region, a discrete intermediate coupling region, and a discrete output coupling region, each of the regions having a plurality of optical device fins disposed on the substrate, the plurality of optical device fins of each region comprising:
at least one first optical device fin having a first slant angle;
at least one second optical device fin having a second slant angle different than the first slant angle;
and at least one third optical device fin having a third slant angle different than the first slant angle and the second slant angle, wherein:
the second slant angle is greater than the first slant angle and the third slant angle is greater than the second slant angle; or
the first slant angle is greater than the second slant angle and the second slant angle is greater than the third slant angle.
2. The device of claim 1 , wherein each of the at least one first optical device fin corresponds to a first portion of optical device fins, the at least one second optical device fin corresponds to a second portion of optical device fins, and the at least one third optical device fin corresponds to a third portion of optical device fins.
3. The device of claim 1 , wherein the first, second, and third slant angles correspond to a rolling k-vector across a surface of the substrate.
4. The device of claim 1 , wherein the plurality of optical device fins include at least one of silicon oxycarbide (SiOC), titanium oxide, titanium oxide nanomaterials, niobium oxide, niobium-germanium (Nb 3 Ge), silicon dioxide (SiO 2 ), silicon oxycarbonitride (SiOCN), vanadium (IV) oxide, aluminum oxide (Al 2 O 3 ), indium tin oxide (ITO), zinc oxide (ZnO), tantalum pentoxide (Ta 2 O 5 ), silicon nitride (Si 3 N 4 ), Si 3 N 4 silicon-rich, Si 3 N 4 hydrogen-doped, Si 3 N 4 boron-doped, silicon carbon nitrate (SiCN), titanium nitride (TiN), zirconium dioxide (ZrO 2 ), germanium (Ge), gallium phosphide (GaP), poly-crystalline (PCD), nanocrystalline diamond (NCD), or doped diamond containing materials.