A semiconductor laser element includes: a first nitride semiconductor layer of a first conductivity-type; a second nitride semiconductor layer of a second conductivity-type; and an active region disposed between the first nitride semiconductor layer and the second nitride semiconductor layer, the active region having a single quantum well structure. The active region comprises a first barrier layer, an intermediate layer, a well layer, and a second barrier layer, in this order in a direction from the first nitride semiconductor layer toward the second nitride semiconductor layer. The thickness of the first barrier layer is 20 nm or less. A lattice constant of the intermediate layer is greater than a lattice constant of each of the first barrier layer and the second barrier layer, and smaller than a lattice constant of the well layer. A thickness of the intermediate layer is greater than a thickness of the well layer.

[Object] To provide a laser element capable of preventing laser characteristics from deteriorating while suppressing electron overflow and improving the yield at the time of production.

[Solving Means] A laser element according to the present technology includes: a first semiconductor layer; a second semiconductor layer; an active layer; and an electron barrier layer. The first semiconductor layer is formed of a group iii nitride semiconductor having a first conducive type. The second semiconductor layer is formed of a group iii nitride semiconductor having a second conductive type. The active layer is formed of a group iii nitride semiconductor and is provided between the first semiconductor layer and the second semiconductor layer. The electron barrier layer is provided between the active layer and the second semiconductor layer and is formed of a group iii nitride semiconductor having a composition ratio of Al larger than that of the second semiconductor layer, a recessed and projecting shape being formed on a surface of the electron barrier layer on a side of the second semiconductor layer, the recessed and projecting shape having a height difference between a projecting portion and a recessed portion in a direction perpendicular to a layer surface direction being 2 nm or more and less than 10 nm.

A novel, monolithically integrated mid-IR optical phased array (OPA) structure which eliminates the wafer bonding process to achieve highly efficient surface emitting optical beam steering in two dimensions is disclosed. Since solar energy is about 15-20 times smaller than that at 1.55 μm, mid-IR is more favorable for the atmospheric transmission due to lower solar radiance backgrounds. For the beam steering, thermo-optic phase shifting is used for azimuthal plane beam steering and laser wavelength tuning is used for elevation plane beam steering. The OPA structure disclosed comprises a wavelength-tunable a QCL, a 1×32 splitter, thermo-optic phase-shifters, and sub-wavelength grating emitters. The disclosed OPA provides a low-cost, low-loss, low-power consumption, robust, small footprint, apparatus that may be used with expendable UAV swarms. A LiDAR may be created by monolithically integrating a QCD with the apparatus. Other embodiments are described and claimed.

A light emitting element (10A) of the present disclosure includes: a stacked structure (20) in which a first compound semiconductor layer (21) having a first surface (21a) and a second surface (21b), an active layer (23), and a second compound semiconductor layer (22) having a first surface (22a) and a second surface (22b) are stacked; a first light reflecting layer (41) formed on a first surface side of the first compound semiconductor layer (21) and having a convex shape in a direction away from the active layer (23); and a second light reflecting layer (42) formed on a second surface side of the second compound semiconductor layer (22) and having a flat shape, in which a partition wall (24) extending in a stacking direction of the stacked structure (20) is formed so as to surround the first light reflecting layer (41).

A light-emitting device that includes a substrate, and at least one column portion, wherein the column portion includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and a light-emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is provided between the substrate and the light-emitting layer, the light-emitting layer includes a first well layer, and a barrier layer, the barrier layer includes a first layer provided between the first semiconductor layer and the first well layer, and the first layer has a cubic crystal structure.

A gas measuring apparatus includes a cell portion, a light source portion, a detection portion, and a control portion. The cell portion includes a space into which a sample gas containing breath containing a first isotope of carbon dioxide and a second isotope of carbon dioxide is introduced. The light source portion changes a wavelength of the light in a band of 4.345 μm or more and 4.384 μm or less. The detection portion performs an operation including first detection of an intensity of the light passing through the space and second detection of an intensity of the light passing through the space into which the sample gas is not introduced. The control portion calculates a ratio of an amount of the second isotope to an amount of the first isotope based on a result of the first detection and a result of the second detection.

A laser diode chip is described. In an embodiment the laser diode chip includes an n-type semiconductor region, a p-type semiconductor region and an active layer arranged between the n-type semiconductor region and the p-type semiconductor region, wherein the active layer is in the form of a single quantum well structure. The single quantum well structure includes a quantum well layer, which is arranged between a first barrier layer and a second barrier layer, wherein the first barrier layer faces the n-type semiconductor region, and the second barrier layer faces the p-type semiconductor region. An electronic bandgap E.sub.QW of the quantum well layer is smaller than an electronic bandgap E.sub.B1 of the first barrier layer and smaller than an electronic bandgap E.sub.B2 of the second barrier layer, and the electronic bandgap E.sub.B1 of the first barrier layer is larger than the electronic bandgap E.sub.B2 of the second barrier layer.

Solid-state optical devices (10) enable tuning of an electrically tunable depletion region (200) to reduce and block lateral (in-junction) carrier spreading. This capability reduces the negative effects of gain-guiding in the junction plane and reduces an astigmatism of an emitted light beam. The tunable depletion region is created by forming a highly resistive Schottky contact (105, 110) or metal-insulator-semiconductor (MIS) structure (205, 210) next to a waveguide (optical mode propagation) and current injection region (215), where lateral spread due to diffusion is expected. The depletion region area is tuned by applying a bias to the highly resistive Schottky contact or the MIS contact structure. Such contacts or similar lossy structures reduce in-junction plane gain-guiding also when unbiased by creating additional optical loss for the mode, thus reducing the effective carrier density participating in light generation, thereby reducing astigmatism.

A quantum cascade laser includes a substrate having a group III-V compound semiconductor and a core region that is provided on the substrate and that includes a group III-V compound semiconductor. The core region includes a plurality of unit structures that are stacked on top of one another. Each of the plurality of unit structures includes an active layer and an injection layer. The injection layer includes at least one strain-compensated layer including a first well layer and a first barrier layer and at least one lattice-matched layer including a second well layer and a second barrier layer. The first well layer has a lattice constant larger than a lattice constant of the substrate. The first barrier layer has a lattice constant smaller than the lattice constant of the substrate. The second well layer and the second barrier layer each have a lattice constant that is lattice-matched to the substrate.

Semiconductor structures involving multiple quantum wells provide increased efficiency of UV and visible light emitting diodes (LEDs) and other emitter devices, particularly at high driving current. LEDs made with the new designs have reduced efficiency droop under high current injection and increased overall external quantum efficiency. The active region of the devices includes separation layers configured between the well layers, the one or more separation regions being configured to have a first mode to act as one or more barrier regions separating a plurality of carriers in a quantum confined mode in each of the quantum wells being provided on each side of the one or more separation layers and a second mode to cause spreading of the plurality of carriers across each of the quantum wells to increase an overlap integral of all of the plurality of carriers. The devices and methods of the invention provide improved efficiency for solid state lighting, including high efficiency ultraviolet LEDs.