The invention relates to a VCSEL structure based on a novel grating reflector. The grating reflector (1) comprises a grating layer (20) with a contiguous core grating region having a grating structure, wherein an index of refraction of high-index sections (21) of the grating structure is at least 2.5, and wherein an index of refraction of low-index sections (22) of the grating structure is less than 2. The core grating region defines a projection in a direction normal to the grating layer. The grating reflector further comprises a cap layer (30) abutting the grating layer (20), and an index of refraction of the cap layer within the projection of the core grating region onto the cap layer is at least 2.5, and within the projection of the core grating region, the cap layer is abutted by a first solid dielectric low-index layer, an index of refraction of the first low-index layer or air being less than 2; and within the projection of the core grating region, the grating layer is also abutted by a second low-index layer and/or by air, an index of refraction of the second low-index layer or air being less than 2. The VCSEL structure furthermore comprises a first reflector and an active region for providing a cavity and amplification. The cap layer (30) may comprise an active layer (32) between cladding layers (31,33) and electrical contacts (35,36) to provide a current through the active layer. Current confinement may be realized by low-index oxide regions (60).

An electrically injected vertical-cavity surface emitting laser (VCSEL) and a method of manufacturing the same is disclosed. The electrically injected VCSEL includes a non-c-plane substrate and a nanoporous bottom distributed Bragg reflector (DBR) comprising a plurality of alternating highly doped III-nitride layers and unintentionally doped III-nitride layers formed above the substrate.

A grating reflector. The grating reflector includes a mesh structure defining a mesh plane and having a thickness normal thereto. The mesh structure includes parallel bars and parallel crossbars, which extend along a direction orthogonal to the bars. The bars and crossbars define a 2D grid of elongated holes, each extending through the mesh structure perpendicular to the mesh plane. The holes are elongated along a direction parallel to the bars and have a substantially rectangular shape with rounded corners. The 2D grid is defined by a cross-shaped unit cell having a bar section and an intersecting crossbar section. The grating reflector has a reflectivity in a bandwidth around a center wavelength higher than 0.99. A ratio between the unit cell volume and the center wavelength in the mesh material cubed is between 1.35 and 1.55.