A light emitting device includes a first active layer on a substrate, a current spreading length, and a plurality of mesa regions on the first active layer. At least a first portion of the first active layer can comprise a first electrical polarity. Each mesa region can include, at least a second portion of the first active layer, a light emitting region on the second portion of the first active layer with a dimension parallel to the substrate smaller than twice the current spreading length, and a second active layer on the light emitting region. The light emitting region can be configured to emit light with a target wavelength from 200 nm to 300 nm. At least a portion of the second active layer can comprise a second electrical polarity.

A laser diode apparatus has a first waveguide layer including a gain region connected in series with a second waveguide layer with a second gain region. A tunnel junction is positioned between the first and second guide layers. A single collimator is positioned in an output path of laser beams emitted from the first and second waveguide layers. The optical beam from the single collimator may be coupled into an optical fiber.

To achieve high-power single transverse mode laser, we here propose a supersymmetry (SUSY)-based triple-ridge waveguide semiconductor laser structure, which is composed of an electrically pumped main broad-ridge waveguide located in the middle and a pair of lossy auxiliary partner waveguides. The auxiliary partner waveguides are designed to provide dissipative modes that can phase match and couple with the higher-order modes in the main waveguide. By appropriately manipulating the gain-loss discrimination of the modes in the laser cavity, one can effectively suppress all the undesired higher-order transverse modes while keeping the fundamental one almost unaffected, thereby ensuring stable single-mode operation with a larger emitting aperture and accordingly a higher output power than a conventional single-transverse-mode ridge waveguide diode laser.

A topological bulk laser includes a topological photonic crystal (32) having an energy band inversion between dipole mode and quadrupole mode near the center of Brillouin zone and a trivial photonic crystal (31) not having band inversion for splicing to each other. The reflection and confinement of an optical field occurs at the interface; and the interface encloses to form a closed contour, thereby forming a laser cavity with an effective cavity feedback for lasing at the interior of the interface. This band-inversion-induced reflection mechanism induces single-mode lasing with directional vertical emission. At room temperature, the topological bulk laser can achieve low threshold, narrow linewidth, and a high side-mode suppression ratio, reduce the fabrication difficulty and costs, and improve heat dissipation and electrical injection efficiency, hence improving lifetime and stability of devices.

A semiconductor disk chip includes a cap layer having at least one structured region for mode selection, a periodic gain structure, a Distributed Bragg reflector, and a substrate. The structured region is structured in such a way that a lateral fundamental mode of the laser radiation experiences lower losses than radiation of higher laser modes and includes at least one trench extending into the cap layer to a depth not greater than a thickness of the cap layer, and wherein the depth decreases from an outer region of an emission surface of the semiconductor chip in a direction of an inner of the emission surface of the semiconductor chip.

A method for manufacturing a light emitting device can include providing a substrate; forming a first active layer with a first electrical polarity; forming a light emitting region configured to emit light with a target wavelength between 200 nm and 300 nm; forming a second active layer with a second electrical polarity; forming a first electrical contact layer, optionally comprising a first optical reflector; removing a portion of the first electrical contact layer, the second active layer, the light emitting region, and the first active layer to form a plurality of mesas; and forming a second electrical contact layer. Each mesa can include a mesa width smaller than 10 times the target wavelength that confines the emitted light from the light emitting region to fewer than 10 transverse modes, or a mesa width smaller than twice a current spreading length of the light emitting device.

A vertical cavity surface emitting laser (VCSEL) has first and second electrical contacts, and an optical resonator. The optical resonator has first and second distributed Bragg reflectors (DBRs), an active layer, a distributed heterojunction bipolar phototransistor (DHBP), and an optical guide. The DHBP has a collector layer, light sensitive layer; a base layer; and an emitter layer. There is an optical coupling between the active layer and the DHBP for providing an active carrier confinement by the DHBP. The optical guide guides an optical mode within the optical resonator during operation. The optical guide is outside a current flow which can be provided by the first and second electrical contacts during operation of the VCSEL. The optical guide is outside a layer sequence between the first and second electrical contacts in the vertical direction of the VCSEL. The optical guide has an oxide aperture arranged in the second DBR.

A laser device includes: a substrate formed from material transparent at a laser wavelength; a first reflecting layer to reflect at least some incident radiation at the laser wavelength; a layer including a gain medium for providing stimulated emission of radiation at the laser wavelength, and positioned between the first reflecting layer and the substrate; a second reflecting layer on an opposite side of the substrate from the first reflecting layer to reflect at least some incident radiation at the laser wavelength; a spatial light modulator in an optical cavity comprising the first and second reflecting layers, and comprising an array of elements each corresponding to a different path for radiation in the optical cavity; and a computer controller that, during operation, causes the spatial light modulator to selectively vary an intensity or phase of radiation in the optical cavity to provide variable transverse spatial mode output of the radiation.

A method for manufacturing a light emitting device can include providing a substrate; forming a first active layer with a first electrical polarity; forming a light emitting region configured to emit light with a target wavelength between 200 nm and 300 nm; forming a second active layer with a second electrical polarity; forming a first electrical contact layer, optionally comprising a first optical reflector; removing a portion of the first electrical contact layer, the second active layer, the light emitting region, and the first active layer to form a plurality of mesas; and forming a second electrical contact layer. Each mesa can include a mesa width smaller than 10 times the target wavelength that confines the emitted light from the light emitting region to fewer than 10 transverse modes, or a mesa width smaller than twice a current spreading length of the light emitting device.

A semiconductor laser device with external resonator with stable longitudinal mode regardless of variation of drive current is disclosed. The device includes: a semiconductor light-emitting element having a pair of end faces with a light emitting section disposed therebetween, and an external resonator configured to oscillate light emitted from the semiconductor light-emitting element, the external resonator being formed by a resonator mirror disposed outside the semiconductor light-emitting element and one of the pair of end faces that is farther from the resonator mirror, wherein, as the semiconductor light-emitting element, a semiconductor light-emitting element having a structure which does not oscillate light emitted therefrom by itself is used. The device further includes a wavelength control element disposed in the optical path within the external resonator and configured to select a wavelength range of the light, and a driver circuit configured to perform fast modulation drive of the semiconductor light-emitting element.