Composition tunable and stable spontaneous emission and lasing in Cd-alloyed perovskite microdisks.

All-inorganic Pb-Cd mixed-cation halide perovskites have emerged as semiconductors exhibiting improved optical and optoelectronic properties. We establish a reliable correlation between photoluminescence and Cd content in bulk CsPbCdBr compositions, propose pathways of photoexcited charge carrier dynamics in them, and show improved stability of lasing in whispering gallery mode microdisks.

A Hybrid System for Defect Detection on Rail Lines through the Fusion of Object and Context Information.

Defect detection on rail lines is essential for ensuring safe and efficient transportation. Current image analysis methods with deep neural networks (DNNs) for defect detection often focus on the defects themselves while ignoring the related context. In this work, we propose a fusion model that combines both a targeted defect search and a context analysis, which is seen as a multimodal fusion task.

Fast switching between the ground- and excited-state lasing in a quantum-dot microdisk triggered by sub-ps pulses.

A quantum-dot microdisk was optically pumped by continuous-wave excitation with a level sufficient for the ground-state lasing. The microdisk was additionally illuminated with sub-ps pulses of various powers. It was found that there is a critical level of pulse power that determines the subsequent transient process of the microlaser.

Two-state lasing in a quantum dot racetrack microlaser.

The peculiarities of two-state lasing in a racetrack microlaser with an InAs/GaAs quantum dot active region are investigated by measuring the electroluminescence spectra at various injection currents and temperatures. Unlike edge-emitting and microdisk lasers, where two-state lasing involves the ground and first excited-state optical transitions of quantum dots, in racetrack microlasers, we observe lasing through the ground and second excited states. As a result, the spectral separation between lasing bands is doubled to more than 150 nm.

Progress of Edge-Emitting Diode Lasers Based on Coupled-Waveguide Concept.

Semiconductor lasers have developed rapidly with the steady growth of the global laser market. The use of semiconductor laser diodes is currently considered to be the most advanced option for achieving the optimal combination of efficiency, energy consumption, and cost parameters of high-power solid-state and fiber lasers. In this work, an approach for optical mode engineering in planar waveguides is investigated.

Temperature Evolution of Two-State Lasing in Microdisk Lasers with InAs/InGaAs Quantum Dots.

One-state and two-state lasing is investigated experimentally and through numerical simulation as a function of temperature in microdisk lasers with Stranski-Krastanow InAs/InGaAs/GaAs quantum dots. Near room temperature, the temperature-induced increment of the ground-state threshold current density is relatively weak and can be described by a characteristic temperature of about 150 K. At elevated temperatures, a faster (super-exponential) increase in the threshold current density is observed.

Submicron-Size Emitters of the 1.2-1.55 μm Spectral Range Based on InP/InAsP/InP Nanostructures Integrated into Si Substrate.

We study photoluminescence of InP/InAsP/InP nanostructures monolithically integrated to a Si(100) substrate. The InP/InAsP/InP nanostructures were grown in pre-formed pits in the silicon substrate using an original approach based on selective area growth and driven by a molten alloy in metal-organic vapor epitaxy method. This approach provides the selective-area synthesis of the ordered emitters arrays on Si substrates.

Improved performance of InGaAs/GaAs microdisk lasers epi-side down bonded onto a silicon board.

We study the impact of improved heat removal on the performance of InGaAs/GaAs microdisk lasers epi-side down bonded onto a silicon substrate. Unlike the initial characteristics of microlasers on a GaAs substrate, the former's bonding results in a decrease in thermal resistance by a factor of 2.3 (1.

InAs/GaAs Quantum Dot Microlasers Formed on Silicon Using Monolithic and Hybrid Integration Methods.

An InAs/InGaAs quantum dot laser with a heterostructure epitaxially grown on a silicon substrate was used to fabricate injection microdisk lasers of different diameters (15-31 µm). A post-growth process includes photolithography and deep dry etching. No surface protection/passivation is applied.

High speed data transmission using directly modulated microdisk lasers based on InGaAs/GaAs quantum well-dots.

We report on direct large signal modulation and the reliability studies of microdisk lasers based on InGaAs/GaAs quantum well-dots. A 23 μm in diameter microlaser exhibits an open eye diagram up to 12.5 Gbit/s and is capable of error-free 10 Gbit/s data transmission at 30°C without temperature stabilization.

Dynamics of Broadband Lasing Cascade from a Single Dot-in-well InGaAs Microdisk.

The development of a fast semiconductor laser is required for the realization of next-generation telecommunication applications. Since lasers operating on quantum dot ground state transitions exhibit only limited gain due to the saturation effect, we investigate lasing from excited states and compare its corresponding static and dynamic behavior to the one from the ground state. InAs quantum dots (QDs) grown in dot-in-well (DWELL) structures allowed to obtain light emission from ground and three excited states in a spectral range of 1.

Highly efficient injection microdisk lasers based on quantum well-dots.

We study injection GaAs-based microdisk lasers capable of operating at room and elevated temperatures. A novel type of active region is used, namely InGaAs quantum well-dots representing a dense array of indium-rich islands formed inside an indium-depleted residual quantum well by metalorganic vapor phase epitaxy. We demonstrate a high output power of 18 mW, a differential efficiency of about 31%, and a peak electrical-to-optical power conversion efficiency of 15% in a 31 μm diameter microdisk laser.

Heat-sink free CW operation of injection microdisk lasers grown on Si substrate with emission wavelength beyond 1.3 μm.

High-performance injection microdisk (MD) lasers grown on Si substrate are demonstrated for the first time, to the best of our knowledge. Continuous-wave (CW) lasing in microlasers with diameters from 14 to 30 μm is achieved at room temperature. The minimal threshold current density of 600  A/cm (room temperature, CW regime, heatsink-free uncooled operation) is comparable to that of high-quality MD lasers on GaAs substrates.

Ultrasmall microdisk and microring lasers based on InAs/InGaAs/GaAs quantum dots.

Unlabelled: Ultrasmall microring and microdisk lasers with an asymmetric air/GaAs/Al0.98Ga0.02As waveguide and an active region based on InAs/InGaAs/GaAs quantum dots emitting around 1.