A semiconductor laser diode is disclosed. In an embodiment a semiconductor laser diode includes a first resonator and a second resonator, the first and second resonators having parallel resonator directions along a longitudinal direction and being monolithically integrated into the semiconductor laser diode, wherein the first resonator includes at least a part of a semiconductor layer sequence having an active layer and an active region configured to be electrically pumped to generate a first light, wherein the longitudinal direction is parallel to a main extension plane of the active layer, and wherein the second resonator has an active region with a laser-active material configured to be optically pumped by at least a part of the first light to produce a second light which is partially emitted outwards from the second resonator.

Included are: an underlying substrate including a first surface; a semiconductor element layer dividable into a plurality of element portions, the semiconductor element layer being located on the first surface of the underlying substrate; and a support substrate including a second surface on which the semiconductor element layer is located, the second surface facing the first surface, the semiconductor element layer being located on the second surface. The support substrate and the semiconductor element layer include a weak portion used to divide the semiconductor element layer into the plurality of element portions.

A Vertical Cavity Surface Emitting Laser (VCSEL) including a light emitting III-nitride active region including quantum wells (QWs), wherein each of the quantum wells have a thickness of more than 8 nm, a cavity length of at least 7 λ, or at least 20 λ, where lambda is a peak wavelength of the light emitted from the active region, layers with reduced surface roughness, a tunnel junction intracavity contact. The VCSEL is flip chip bonded using In—Au bonding. This is the first report of a VCSEL capable of continuous wave operation.

A method for tuning the frequency of THz radiation is provided. The method utilizes an apparatus comprising a spin injector, a tunnel junction coupled to the spin injector, and a ferromagnetic material coupled to the tunnel junction. The ferromagnetic material comprises a Magnon Gain Medium (MGM). The method comprises the step of applying a bias voltage to shift a Fermi level of the spin injector with respect to the Fermi level of the ferromagnetic material to initiate generation of non-equilibrium magnons by injecting minority electrons into the Magnon Gain Medium. The method further comprises the step of tuning a frequency of the generated THz radiation by changing the value of the bias voltage.

A semiconductor light emitting device includes a substrate and a semiconductor multilayer stacked on the substrate. The semiconductor multilayer includes an n-side clad layer stacked above the substrate, an active layer stacked above the n-side clad layer, and a p-side clad layer stacked above the active layer. The semiconductor multilayer includes a first plane perpendicular to a stacking direction in which the semiconductor multilayer is stacked, and a lattice constant inside the first plane is an anisotropy constant.

In order to provide a QCL element operating in the near-infrared wavelength range, the present disclosure provides a quantum cascade laser element 1000 having a semiconductor superlattice structure (QCL structure 100) sandwiched between a pair of conductive sections 20 and 30. The semiconductor superlattice structure serves as an active region that emits electromagnetic waves. The active region has a plurality of unit structures 10U that are stacked on top of each other. Each unit structure includes four well layers 10W1-10W4 of a composition of Al.sub.xGa.sub.1−xN, separated from each other by barrier layers 10B1-10B5 of a composition of Al.sub.yGa.sub.1−yN with 0≤x<y≤1. Both of the conductive sections in the pair of conductive sections have a refractive index lower than that of the active region in which doped TCO inserted as a key role.

A reflecting mirror includes a first film and a second film on the first film, and has a reflection band where a center wavelength is λ. The first film includes a layer having a first average refractive index and another layer having a second average refractive index higher than the first average refractive index. The second film includes a layer having a third average refractive index and another layer having a fourth average refractive index higher than the third average refractive index. A sum of optical film thicknesses of the two layers of the first film is λ/2. A sum of optical film thicknesses of the two layers of the second film is greater than or equal to (n+1)λ/2 (n is an integer greater than or equal to 1).

A light emitter includes a substrate, a first semiconductor layer having a first conductivity type, a second semiconductor layer having a second conductivity type different from the first conductivity type, a light emitting layer provided between the first semiconductor layer and the second semiconductor layer and capable of emitting light when current is injected into the light emitting layer, and a third semiconductor layer provided between the substrate and the first semiconductor layer and having the second conductivity type, in which the first semiconductor layer is provided between the third semiconductor layer and the light emitting layer, and the third semiconductor layer has a protruding/recessed structure.

A laser diode chip includes a removable substrate, a first semiconductor layer disposed on the removable substrate, an emitting layer disposed on one part of the first semiconductor layer, a second semiconductor layer disposed on the emitting layer and forming a ridge mesa, a current conducting layer disposed on another part of the first semiconductor layer, a patterned insulating layer covering the second semiconductor layer and the current conducting layer and including a first zone and a second zone which respectively expose a part of the current conducting layer and a part of the second semiconductor layer, a first electrode and a second electrode respectively disposed on the first zone and the second zone. A projection of the ridge mesa projected to the removable substrate covers a part of projections of the first electrode and the second electrode projected to the removable substrate.

A device includes a first cladding layer, a waveguide laser, an absorption layer, and a second cladding layer. The absorption layer is constituted by an oversaturation absorption body such as graphene. Also, the absorption layer is provided between the active layer and the distributed Bragg reflection portion. The absorption layer is formed below a core forming an optical waveguide between the active layer and a distributed Bragg reflection portion.