Patent ID: 11867912
Assignee: nan
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 9:
10. An optical system, comprising:
a slanted grating metasurface formed on a planar face of a waveguide to couple optical radiation passing through the waveguide back into the waveguide for conveyance along a length of the waveguide, the slanted grating metasurface comprising:
an array of elongated silicon nitride ridges extending along a width of the waveguide, wherein a cross-section of each elongated silicon nitride ridge approximates a triangle; and
a reflective metallic layer positioned on the elongated silicon nitride ridges,

wherein an internal angle of an angled face of each elongated silicon nitride ridge is less than 25 degrees relative to the planar face of the waveguide,
wherein each elongated silicon nitride ridge extends to a height between 70 and 200 nanometers from the planar face of the waveguide, and
wherein a pitch between adjacent elongated silicon nitride ridges is between 300 and 500 nanometers.