In some implementations, an emitter device includes a substrate layer and epitaxial layers on the substrate layer. The epitaxial layers may include a first mirror, a second mirror, and an active layer between the first mirror and the second mirror. The epitaxial layers may include at least one oxidation layer including a first oxidized region and a second oxidized region separate from the first oxidized region. The first oxidized region and the second oxidized region may be configured to provide a strain on the epitaxial layers that is radially asymmetric. The epitaxial layers may include a set of oxidation trenches in the set of epitaxial layers to expose the at least one oxidation layer.

An emitter array, may comprise a first set of emitters that has a nominal optical output power at an operating voltage. The emitter array may comprise a second set of emitters that has substantially less than the nominal optical output power or no optical output power at the operating voltage. The first set of emitters and the second set of emitters may be interleaved with each other to form a two-dimensional regular pattern of emitters that emits a random pattern of light at the nominal optical output power at the operating voltage. The first set of emitters and the second set of emitters may be electrically connected in parallel.

In some embodiments, the present disclosure relates to a method of making a microlens for a VCSEL device. The method includes forming a first lens layer over a second reflector layer. The first lens layer has a first average concentration of a first element. A first additional reflector layer is formed over the first lens layer. A second lens layer is formed over the first additional reflector layer. The second lens layer has a second average concentration of the first element greater than the first average concentration. A second additional reflector layer is formed over the second lens layer. An oxidation process is performed to oxidize peripheral portions of the first and second lens layers to form oxidized peripheral portions of the first and second lens layer. The oxidized peripheral portions of the second lens layer are wider than the oxidized peripheral portions of the first lens layer.

An optoelectronic device includes a semiconductor substrate. A first set of thin-film layers is disposed on the substrate and defines a lower distributed Bragg-reflector (DBR) stack. A second set of thin-film layers is disposed over the lower DBR stack and defines an optical emission region, which is contained in a mesa defined by multiple trenches, which are disposed around the optical emission region without fully surrounding the optical emission region. A third set of thin-film layers is disposed over the optical emission region and defines an upper DBR stack. Electrodes are disposed around the mesa in gaps between the trenches and are configured to apply an excitation current to the optical emission region.

Provided is a laser device including a lower reflective layer, a laser cavity comprising an active layer disposed on the lower reflective layer, an upper reflective layer disposed on the laser cavity, and a blocking structure disposed between the laser cavity and the upper reflective layer, in which the blocking structure includes a first intermediate layer disposed on the laser cavity, a blocking layer disposed on the first intermediate layer and including a through-hole, and a second intermediate layer disposed on the blocking layer.

A surface emitting laser device includes: a first semiconductor layer of a first conductive type; a second semiconductor layer including a first light reflecting layer of the first conductive type, a light generating layer, and a second light reflecting layer of a second conductive type, which are laminated in this order from a first semiconductor layer side; a laser diode structure partitioned in a plateau shape including a top surface by a removal portion in which the second semiconductor layer is dug down, and configured to emit a laser beam to the first semiconductor layer side; a first insulating layer formed inside the laser diode structure; and a second insulating layer covering the top surface.

A vertical cavity surface emitting laser (VCSEL) device includes a microlens arranged over a reflector stack. The reflector stack includes alternating reflector layers of a first material and a second material. The microlens stack includes a first lens layer, a second lens layer arranged over the first lens layer, and a third lens layer arranged over the second lens layer. The first lens layer includes a first average concentration of a first element and has a first width. The second lens layer includes a second average concentration of the first element greater than the first average concentration and has a second width smaller than the first width. The third lens layer includes a third average concentration of the first element greater than the second average concentration and has a third width smaller than the second width.

A VCSEL device having non-coaxial-with-one-another apertures and/or rotationally asymmetric apertures formed in layer(s) of the VCSEL structure to define more than one spatial mode in a light output in operation of the device. An array of such VCSEL devices configured to have different spatial modes at the output of different constituent VCSEL devices. Spatial asymmetry of structure of the constituent VCSEL devices and, therefore, arrays of VCSEL devices causes the overall light output to form an irregular grid of output spots of light. When the VCSEL array is equipped with an appropriate lens array, the spatial components of the light output of the VCSEL array are caused to overlap in the far at the imaging plane in a multiple spatial (and spectral) mode fashion, thereby reducing speckle in imaging applications.

An exemplary embodiment of the invention relates to a method of fabricating a radiation emitter (100) comprising the steps of fabricating a layer stack (10) that comprises a first reflector (12), an active region (13), an oxidizable layer (21-24), and a second reflector (14); and locally removing the layer stack (10), and thereby forming a mesa (M) of the radiation emitter (100), wherein said mesa (M) comprises the first reflector (12), the active region (13), the oxidizable layer (21-24) and the second reflector (14), wherein before or after locally removing the layer stack (10) and forming said mesa (M) the following steps are carried out: vertically etching blind holes (30) inside the layer stack (10), wherein the blind holes (30) vertically extend at least to the oxidizable layer (21-24) and expose the oxidizable layer (21-24); and oxidizing the oxidizable layer (21-24) via the sidewalls (31) of the blind holes (30) in lateral direction, wherein from each hole an oxidation front (32) radially moves outwards and wherein the etching is terminated before the entire oxidizable layer (21-24) is oxidized, thereby forming at least two unoxidized apertures, (40) each of which is limited by at least three oxidation fronts (32), inside the mesa.

An array of surface-emitting lasers is provided. The array outputs high brightness in a unipolar way. The array comprises a stress-adjustment unit and a plurality of epitaxial device units. The stress-adjustment unit is used to adjust stress. The stress from a substrate is used to select a laser mode for an aperture unit. The selection of the laser mode is enhanced for the aperture unit without sacrificing driving current. Low current operation is achieved in a single mode for effectively reducing volume and further minimizing the size of the whole array to achieve high-quality laser output. An object can be scanned by the outputted laser to obtain a clear image with a high resolution. Hence, the present invention is applicable for face recognition with high recognition and high security.