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

Claim 0:
1. An optical system, comprising:
a waveguide;
an optical source to generate optical radiation incident on a first face of the waveguide at an angle of incidence at which the optical radiation passes through the waveguide and out of a second face of the waveguide that is opposite the first face of the waveguide; and
a metasurface on the second face of the waveguide to receive the optical radiation that passes through the waveguide from the optical source, wherein the metasurface is operable to reflect the optical radiation back into the waveguide at an angle greater than a critical angle for total internal reflection within the waveguide, such that the optical radiation is conveyed along a length of the waveguide,
wherein the metasurface comprises:
a slanted grating of angled ridges extending parallel to one another along a width of the waveguide and perpendicular to the length of the waveguide; and
a reflective metallic layer over the array of angled ridges, and

wherein each angled ridge of the slanted grating comprises:
a base face that is co-planar with the second face of the waveguide;
a height face that extends from the base face to a ridge height with an internal angle greater than 60 degrees relative to the base face; and
an angled face that extends between an edge of the base face and an edge of the height face at a target internal angle less than 25 degrees relative to the base face.