We demonstrate how the presence of gain-loss contrast between two coupled identical resonators can be used as a new degree of freedom to enhance the modulation frequency response of laser diodes. An electrically pumped microring laser system with a bending radius of 50 μm is fabricated on an InAlGaAs/InP MQW p-i-n structure. The room temperature continuous wave (CW) laser threshold current of the device is 27 mA. By adjusting the ratio between the injection current levels in the two coupled microrings, our experimental results clearly show a bandwidth improvement by up to 1.63 times the fundamental resonant frequency of the individual device. This matches well with our rate equation simulation model.
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http://dx.doi.org/10.1364/OE.442076 | DOI Listing |
J Am Chem Soc
January 2025
Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
High mobility emissive organic semiconductors (HMEOSCs) are a kind of unique semiconducting material that simultaneously integrates high charge carrier mobility and strong emission features, which are not only crucial for overcoming the performance bottlenecks of current organic optoelectronic devices but also important for constructing high-density integrated devices/circuits for potential smart display technologies and electrically pumped organic lasers. However, the development of HMEOSCs is facing great challenges due to the mutually exclusive requirements of molecular structures and packing modes between high charge carrier mobility and strong solid-state emission. Encouragingly, considerable advances on HMEOSCs have been made with continuous efforts, and the successful integration of these two properties within individual organic semiconductors currently presents a promising research direction in organic electronics.
View Article and Find Full Text PDFHeliyon
January 2025
North China Electric Power University, Department of Power Engineering, China.
In the context of global efforts toward energy transition and carbon neutrality, thermal integrated pumped thermal energy storage (TIPTES) systems, especially those utilizing low-grade heat sources, have garnered significant attention due to their large capacity, flexibility, and environmental advantages. This paper explores a TIPTES system that harnesses industrial waste heat as a heat source. The system's heat pump (HP) subcycle and Organic Rankine Cycle (ORC) subcycle are equipped with regenerators to optimize system configuration and enhance efficiency.
View Article and Find Full Text PDFRSC Adv
January 2025
Faculty of Materials Science and Engineering, Phenikaa University Yen Nghia, Ha-Dong District Hanoi 10000 Vietnam
Near-ultraviolet (NUV)-pumped white light-emitting-diodes (WLEDs) often suffer from poor color rendering in the 480-520 nm range, highlighting the need for an efficient cyan phosphor with strong absorption at 370-420 nm. This study presents the successful synthesis of cyan-emitting ZnS/ZnO phosphors using a high-energy planetary ball milling method followed by post-annealing. The fabricated phosphors, with particle sizes ranging from 1 to 3 μm, exhibit strong cyan emission with CIE chromaticity coordinates of (0.
View Article and Find Full Text PDFPLoS One
January 2025
Electrical Engineering Department, Faculty of Engineering, Al-Baha University, Al-Baha, Saudi Arabia.
This paper investigates enhancing the efficiency of solar water pumping systems (SWPS) by implementing a Maximum Power Point Tracking technique based on the Bat Metaheuristic Optimizer (MPPT-bat) for the photovoltaic generator (PVG) side, coupled with Direct Torque Control (DTC) for the induction motor powering the pump. Unlike traditional techniques, which make no compromise between tracking speed, oscillation and robustness. The integration of the MPPT-bat represents a significant advance, making it possible to improve PVG performance whatever the weather conditions.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
Department of Electrical Engineering, TUM School of Computation, Information and Technology, Technical University of Munich, 80333 Munich, Germany.
Despite major advances in the field of actuator technology for microsystems, miniaturized microfluidic actuation systems for mobile devices are still not common in the market. We present a micropump concept and an associated mass flow sensor design, which, in combination, have the potential to form the basis for an integrated microfluidic development platform for microfluidic systems in general and microdosing systems in particular. The micropump combines the use of active valves with an electrostatic drive principle for the pump membrane and the valves, respectively.
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