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Full-Text Articles in Nanoscience and Nanotechnology
Integrating Non-Planar Metamaterials With Magnetic Absorbing Materials To Yield Ultra-Broadband Microwave Hybrid Absorbers, Wei Li, Tianlong Wu, Wei Wang, Jianguo Guan, Pengcheng Zhai
Integrating Non-Planar Metamaterials With Magnetic Absorbing Materials To Yield Ultra-Broadband Microwave Hybrid Absorbers, Wei Li, Tianlong Wu, Wei Wang, Jianguo Guan, Pengcheng Zhai
Birck and NCN Publications
Broadening the bandwidth of electromagnetic wave absorbers has greatly challenged material scientists. Here, we propose a two-layer hybrid absorber consisting of a non-planar metamaterial (MM) and a magnetic microwave absorbing material (MAM). The non-planar MM using magnetic MAMs instead of dielectric substrates shows good low frequency absorption and low reflection across a broad spectrum. Benefiting from this and the high frequency strong absorption of the MAM layer, the lightweight hybrid absorber exhibits 90% absorptivity over the whole 2-18 GHz range. Our result reveals a promising and flexible method to greatly extend or control the absorption bandwidth of absorbers. (C) 2014 …
Non-Equilibrium Green's Function Calculation For Gan-Based Terahertz-Quantum Cascade Laser Structures, H. Yasuda, T. Kubis, I. Hosako, K. Hirakawa
Non-Equilibrium Green's Function Calculation For Gan-Based Terahertz-Quantum Cascade Laser Structures, H. Yasuda, T. Kubis, I. Hosako, K. Hirakawa
Birck and NCN Publications
We theoretically investigated GaN-based resonant phonon terahertz-quantum cascade laser (QCL) structures for possible high-temperature operation by using the non-equilibrium Green's function method. It was found that the GaN-based THz-QCL structures do not necessarily have a gain sufficient for lasing, even though the thermal backfilling and the thermally activated phonon scattering are effectively suppressed. The main reason for this is the broadening of the subband levels caused by a very strong interaction between electrons and longitudinal optical (LO) phonons in GaN. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4704389]