Abstract: A device having a broad-band, white incident angle range anti-reflection coating disclosed. The device includes a substrate having a first refractive index, at least one interference layer disposed on top of the substrate; and a gradient index optical layer. The gradient index optical layer has a gradient refractive index disposed on top of the at least one high index optical layer. The gradient index optical layer has a bottom refractive index at a bottom surface of the gradient index optical layer and a top refractive index at a top surface of the gradient index optical layer. The gradient refractive index of the gradient index optical layer decreases gradually from the bottom surface to the top surface. The at least one interference layer has a refractive index between the first refractive index of the substrate and the bottom refractive index of the gradient index optical layer.

Abstract: At least one embodiment in the disclosure describes a high efficiency directional light engine. The light engine comprises a light emitter emitting light and a collimation lens. The collimation lens has a cone-shaped sidewall, a base surface and a curved top surface. The height of the cone-shaped sidewall is at least three times more than the diameter of the base surface. The light emitter is optically coupled to and disposed in close proximity to the base surface. One or more first reflection images of the light emitter result from first reflection of the light off a surface of the cone-shaped sidewall. The diameter of the light emitter is substantially close to the diameter of the base surface so that the light emitter and the first reflection images form a virtual point light source with minimal gap(s) or without any gap between the light emitter and the first reflection images.

Abstract: At least one embodiment in the disclosure describes a high efficiency directional light engine. The light engine comprises a light emitter emitting light and a collimation lens. The collimation lens has a cone-shaped sidewall, a base surface and a curved top surface. The height of the cone-shaped sidewall is at least three times more than the diameter of the base surface. The light emitter is optically coupled to and disposed in close proximity to the base surface. One or more first reflection images of the light emitter result from first reflection of the light off a surface of the cone-shaped sidewall. The diameter of the light emitter is substantially close to the diameter of the base surface so that the light emitter and the first reflection images form a virtual point light source with minimal gap(s) or without any gap between the light emitter and the first reflection images.

Abstract: At least one embodiment in the disclosure describes a high efficiency directional light engine. The light engine comprises a light emitter emitting light and a collimation lens. The collimation lens has a cone-shaped sidewall, a base surface and a curved top surface. The height of the cone-shaped sidewall is at least three times more than the diameter of the base surface. The light emitter is optically coupled to and disposed in close proximity to the base surface. One or more first reflection images of the light emitter result from first reflection of the light off a surface of the cone-shaped sidewall. The diameter of the light emitter is substantially close to the diameter of the base surface so that the light emitter and the first reflection images form a virtual point light source with minimal gap(s) or without any gap between the light emitter and the first reflection images.

Abstract: At least one embodiment in the disclosure describes a high efficiency directional light engine. The light engine comprises a light emitter emitting light and a cone-shaped mirror having a base opening. The light emitter is disposed near or at the base opening. Light emitted from the light emitter is reflected off the cone-shaped mirror and results in one or more first reflection images. The light emitter occupies a substantial portion of the base opening such that the light emitter and the first reflection images forms a virtual point light source without a significant gap(s) between the light emitter and the first reflection images.

Abstract: There is herein described an optical filter. The optical filter includes a substrate and a plurality of at least four optical thin film layers. The optical thin film layers are disposed on top of the substrate. Each of the optical thin film layers has an effective refractive index different from effective refractive indices of the immediate upper and lower optical thin film layers. At least one of the optical thin film layers is a thickness tunable nano-feature layer. The nano-feature layer contains a plurality of flexible nano-features. At least one of the optical thin film layers is a dense layer.

Abstract: An optoelectronic light emitting semiconductor device is provided comprising an active region, a p-type Group III nitride layer, an n-type Group III nitride layer, a p-side metal contact layer, an n-side metal contact layer, and an undoped tunneling enhancement layer. The p-side metal contact layer is characterized by a work function W satisfying the following relation: W?e?AFF±0.025 eV where e?AFF is the electron affinity of the undoped tunneling enhancement layer. The undoped tunneling enhancement layer and the p-type Group III nitride layer comprise conduction and valence energy bands. The top of the valence band V1 of the undoped tunneling enhancement layer is above the top of the valence band V2 of the p-type Group III nitride layer at the band offset interface to generate a capacity for a relatively high concentration of holes in the undoped tunneling enhancement layer at the band offset interface. Additional embodiments are disclosed and claimed.

Abstract: Methods of fabricating a metal contact structure for a laser diodes are provided, wherein the method comprises providing a UV transparent semiconductor substrate, a UV transparent semiconductor epilayer defining a ridge disposed between etched epilayer edges, the epilayer being disposed over the UV transparent semiconductor substrate, and a UV opaque metal layer disposed over the epilayer ridge, applying at least one photoresist layer (positive photoresist, image reversal photoresist, or negative photoresist) over the opaque metal layer and epilayer edges, and selectively developing regions of the photoresist layer via backside exposure to UV light with the opaque metal layer used as a photolithographic mask.

Abstract: Methods of fabricating a metal contact structure for a laser diodes are provided, wherein the method comprises providing a UV transparent semiconductor substrate, a UV transparent semiconductor epilayer defining a ridge disposed between etched epilayer edges, the epilayer being disposed over the UV transparent semiconductor substrate, and a UV opaque metal layer disposed over the epilayer ridge, applying at least one photoresist layer (positive photoresist, image reversal photoresist, or negative photoresist) over the opaque metal layer and epilayer edges, and selectively developing regions of the photoresist layer via backside exposure to UV light with the opaque metal layer used as a photolithographic mask.