In this work, the authors propose and experimentally demonstrate a large-area long-wavelength infrared thermal emitter, which is spectrally selective, highly directional, and easily fabricated.
Biogeography-based optimization (BBO) algorithm is not good at dealing with regions where function values change dramatically or barely. A novel biogeography-based optimization algorithm is proposed in this paper based on Momentum migration and taxonomic mutation. The momentum item is added to the original migration operation of BBO. It makes the algorithm more advantageous in dealing with regions where function values change dramatically or barely. At the same time, taxonomic mutation strategy divides the solutions into three categories: promising class, middle class and inferior class. Promising solutions do not take part in this mutation operation. Solutions of middle class use balanced differential mutation, and inferior solutions adopt exploration-biased random mutation. This strategy further increases the diversity of population. The simulation experiments are carried out with different types of CEC2014 benchmark functions. The proposed algorithm is compared with other algorithms and shows stronger global search ability, faster convergence speed and higher convergence accuracy.
Mid-infrared (MIR) semiconductor laser sources are essential for applications in gas detection, infrared imaging, and high-speed free space optical communications. At present, the dynamic wavelength tunability of MIR lasers based on lead salt, antimonide, and quantum cascade lasers is limited and their compact size as well as heterogeneous integration are still challenging. Two-dimensional (2D) materials, used as optical gain materials, have the flexible tunability and compatible van der Waals integrations-providing many new possibilities for constructing MIR laser sources of large tunability and high integration. Here, wide-wavelength tunable MIR vertical cavity surface emitting lasers (VCSELs) integrated on silicon substrates are realized based on 2D black arsenic phosphorus (b-As x P 1−x ). The emission wavelength of the optically pumped laser device is demonstrated to be tuned from 3.42 to 4.65 μm at room temperature, which could be controlled by adjusting the alloy composition and thickness of the gain media b-As x P 1−x . The tunable MIR VCSEL device would pave the way for further exploration of 2D materials-based IR lasers working as on-chip light sources.
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