The invention relates to a waveguide having a partially transparent incoupling portion, having a decoupling portion which is spaced apart from the incoupling portion in the lateral direction, having a substantially transparent base body which is outside of the incoupling portion and outside of the decoupling portion, wherein the transparent base body has a front side and a rear side, the wave guide having a diffractive incoupling structure in the incoupling portion and the waveguide having a decoupling structure in the decoupling portion, the diffractive incoupling structure being designed to diffract radiation coming from an object to be detected and incident on a front side of the waveguide in the incoupling portion only in part such that the diffracted part propagates to the decoupling portion by reflections in the base body as incoupled radiation, wherein the decoupling structure deflects at least one part of the incoupled radiation incident thereon such that the deflected part exits the base body in the decoupling portion via the front side or the rear side of the base body as decoupled radiation, and wherein the diffractive incoupling structure has at least one diffractive efficiency which continually decreases toward one edge of the incoupling portion.

The invention relates to a waveguide having a partially transparent incoupling portion, having a decoupling portion which is spaced apart from the incoupling portion in the lateral direction, having a substantially transparent base body which is outside of the incoupling portion and outside of the decoupling portion, wherein the transparent base body has a front side and a rear side, the wave guide having a diffractive incoupling structure in the incoupling portion and the waveguide having a decoupling structure in the decoupling portion, the diffractive incoupling structure being designed to diffract radiation coming from an object to be detected and incident on a front side of the waveguide in the incoupling portion only in part such that the diffracted part propagates to the decoupling portion by reflections in the base body as incoupled radiation, wherein the decoupling structure deflects at least one part of the incoupled radiation incident thereon such that the deflected part exits the base body in the decoupling portion via the front side or the rear side of the base body as decoupled radiation, and wherein the diffractive incoupling structure has at least one diffractive efficiency which continually decreases toward one edge of the incoupling portion.

A waveguide display includes a waveguide and a grating coupler configured to couple display light into or out of the waveguide. The grating coupler includes at least a first grating layer and a second grating layer arranged in a stack. The first grating layer is characterized by a first thickness and includes a first transmission VBG configured to diffract display light of a first wavelength from a first field of view. The second grating layer is characterized by a second thickness greater than the first thickness and includes a second transmission VBG configured to diffract display light of the first wavelength from a second field of view greater than the first field of view.

A waveguide display includes a waveguide and a grating coupler configured to couple display light into or out of the waveguide. The grating coupler includes at least a first grating layer and a second grating layer arranged in a stack. The first grating layer is characterized by a first thickness and includes a first transmission VBG configured to diffract display light of a first wavelength from a first field of view. The second grating layer is characterized by a second thickness greater than the first thickness and includes a second transmission VBG configured to diffract display light of the first wavelength from a second field of view greater than the first field of view.

A diffractive optical element includes: a substrate; a protrusion and recess portion that is formed on one surface of the substrate and imposes predetermined diffraction on incident light; and an antireflection layer provided between the substrate and the protrusion and recess portion. An effective refractive index difference Δn in a wavelength range of the incident light between a first medium constituting a protrusion of the protrusion and recess portion and a second medium constituting a recess of the protrusion and recess portion is 0.70 or more. An exit angle range θ.sub.out of diffraction light exiting from the protrusion and recess portion when the incident light enters the substrate from a normal direction of the substrate is 60° or more. Total efficiency of diffraction light exiting from the protrusion and recess portion in the exit angle range is 65% or more.

A diffractive optical element includes: a substrate; a protrusion and recess portion that is formed on one surface of the substrate and imposes predetermined diffraction on incident light; and an antireflection layer provided between the substrate and the protrusion and recess portion. An effective refractive index difference Δn in a wavelength range of the incident light between a first medium constituting a protrusion of the protrusion and recess portion and a second medium constituting a recess of the protrusion and recess portion is 0.70 or more. An exit angle range θ.sub.out of diffraction light exiting from the protrusion and recess portion when the incident light enters the substrate from a normal direction of the substrate is 60° or more. Total efficiency of diffraction light exiting from the protrusion and recess portion in the exit angle range is 65% or more.

In various embodiments, laser devices include a thermal bonding layer featuring an array of carbon nanotubes and at least one metallic thermal bonding material.

In various embodiments, laser devices include a thermal bonding layer featuring an array of carbon nanotubes and at least one metallic thermal bonding material.

Disclosed herein is methods and apparatus for recording a holographic waveguide utilizing an inverted holographic master technique. In some embodiments, an apparatus for recording a holographic waveguide is provided. The apparatus may include a source of light configured to provide a recording beam; a master substrate with a non-grating modulated surface and a grating modulated surface, wherein the grating modulated surface is opposite to the non-grating modulated surface and is configured to diffract the recording beam; a bottom substrate with opposing light transmitting surfaces coated with anti-reflection coatings overlaying the grating modulated surface of the substrate and separated from the master substrate by a gap; and an exposure cell containing holographic recording material directly facing the non-grating modulated surface of the master substrate. Advantageously, the inverted holographic master technique mitigates the effects of unwanted reflected exposure light.

Disclosed herein is methods and apparatus for recording a holographic waveguide utilizing an inverted holographic master technique. In some embodiments, an apparatus for recording a holographic waveguide is provided. The apparatus may include a source of light configured to provide a recording beam; a master substrate with a non-grating modulated surface and a grating modulated surface, wherein the grating modulated surface is opposite to the non-grating modulated surface and is configured to diffract the recording beam; a bottom substrate with opposing light transmitting surfaces coated with anti-reflection coatings overlaying the grating modulated surface of the substrate and separated from the master substrate by a gap; and an exposure cell containing holographic recording material directly facing the non-grating modulated surface of the master substrate. Advantageously, the inverted holographic master technique mitigates the effects of unwanted reflected exposure light.