Single-mode lasing at room temperature in quantum-cascade lasers (QCLs) with arched cavity design has been demonstrated. The output optical power in single-mode lasing regime at ~7.7-μm lasing wavelength was above 6 mW with a side-mode suppression ratio of up to 25 dB. The QCL heterostructure for the arched cavities was grown by molecular-beam epitaxy (MBE) based on a heterojunction of In_0.53Ga_0.47As/Al_0.48In_0.52As solid alloys, lattice-matched with InP substrate, and InP layers performing the function of waveguide claddings.

Методом молекулярно-пучковой эпитаксии продемонстрирована возможность изготовления гетероструктур квантово-каскадных лазеров спектрального диапазона 7-8 mum, содержащих в активной области 50 квантовых каскадов на основе гетеропары твердых растворов In0.53Ga0.47As/Al0.48In0.52As. Для получения оптического излучения использована конструкция квантового каскада, основанная на принципе двухфононного резонансного рассеяния. Методами рентгеновской дифракции и просвечивающей электронной микроскопии исследованы структурные свойства созданных гетероструктур и подтверждено их высокое структурное совершенство --- идентичность состава и толщин эпитаксиальных слоев во всех 50 каскадах. Полосковые лазеры, изготовленные из гетероструктуры, демонстрируют лазерную генерацию с пороговой плотностью тока менее 1.6 kA/cm2 при температуре 78 K. DOI: 10.21883/PJTF.2017.14.44833.16776

The heterostructure of a quantum-cascade laser based on In0.53Ga0.47As/Al0.48In0.52As heteropair lattice matched with the InP was grown by molecular beam epitaxy. InP layers was used to form the optical waveguide. Room temperature lasing in the spectral range of 8 μm in the standard ridge geometry of a Fabry-Perot cavity formed by cleaved facets with peak output optical power of 0.45 W was obtained.

Room-temperature lasing at a wavelength of 8 μm in multistage quantum-cascade lasers pumped by current pulses is demonstrated. A quantum-cascade laser heterostructure based on the In_0.53Ga_0.47As/A_l0.48In_0.52As alloy heteropair, matched to an InP substrate, is grown by molecular-beam epitaxy and consists of 50 identical cascades placed in a waveguide with air as the top cladding. A threshold current density of ~5.1 kA/cm^2 at a temperature of 300 K is obtained in ridge lasers with a cavity length of 1.4 mm and a ridge width of 24 μm.

The results of the study of heterostructures based on short-period InGaAs/InGaAlAs superlattices fabricated by molecular beam epitaxy on an InP substrate with the aim of using them as active regions for vertical-cavity surface emitting lasers of the 1.3 μm spectral range are studied. Photoluminescence and X-ray diffraction studies of the fabricated heterostructures are carried out. It was shown that a change in the ratio of the quantum well thickness and the barrier layer thickness of the superlattice allows one to controllably shift the position of the photoluminescence peak and to provide the heterostructure parameters necessary to achieve lasing at a wavelength of 1.3 μm, while the photoluminescence efficiency remains practically unchanged.