Wavelength selection criteria for laser communications

Shaik, Kamran S.; Hemmati, Hamid

doi:10.1117/12.207422

Cited by 7 publications

(2 citation statements)

References 32 publications

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“…As expected the results were unchanged. Although not stated in the article, we now know that the results in ref b were obtained using internal coordinates not mass-weighted. This method does not lead to the IRC (even if the program “Gaussian” used calls it “IRC”) but to a reaction path that may depend on the definition of the internal coordinates employed.…”

Section: Outersphere Electron Transfer Innersphere Electron Transfer ...mentioning

confidence: 98%

Are Anion Radicals Nucleophiles and/or Outersphere Electron Donors? An Ab Initio Study of the Reaction of Ethylene and Formaldehyde Anion Radicals with Methyl Fluoride and Chloride

et al. 1996

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Ab initio calculations combined with an intrinsic reaction coordinate analysis of the title reactions have allowed the identification as well as the geometric and thermodynamic characterization of two types of reaction paths on the same potential energy hypersurface. One involves an outersphere electron transfer from the anion radical which dissociatively reduces the methyl halide acceptor into the methyl radical and the halide ion. The other pathway leads to substitution (two pathways leading to O- and C-substitution repectively in the case of CH2O•-). The substitution transition states have a tighter geometry than the outersphere transition state and may be viewed equivalently as SN2 reactions or innersphere electron transfers concerted with bond cleavage and bond formation. In the competition between the two types of processes, because of bonded interactions in the transition state, SN2 substitution has a lower energy barrier than the outersphere reaction. Owing to the looser geometry of its transition state, entropy favors the outersphere pathway. This factor is not sufficient to reverse the free energy balance with the reactants investigated but this is predicted to occur with sterically hindered systems.

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Section: Outersphere Electron Transfer Innersphere Electron Transfer ...mentioning

confidence: 98%

Are Anion Radicals Nucleophiles and/or Outersphere Electron Donors? An Ab Initio Study of the Reaction of Ethylene and Formaldehyde Anion Radicals with Methyl Fluoride and Chloride

et al. 1996

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“…For space-based applications terahertz has several advantages over conventional RF communications: (1) higher data rate due to wider channel bandwidth, (2) improved security from narrower beam widths and higher attenuation in the atmosphere, and (3) compact size/volume (e.g., smaller antenna size for same directivity) [99], which may also reduce launching costs. In comparison to laser-based communication systems, terahertz systems can also have a much more reliable link establishment between terrestrial stations and satellites under varying whether conditions [100,101].…”

Section: Space-based Terahertz Systemsmentioning

confidence: 99%

A Perspective on Terahertz Next-Generation Wireless Communications

et al. 2019

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In the past year, fifth-generation (5G) wireless technology has seen dramatic growth, spurred on by the continuing demand for faster data communications with lower latency. At the same time, many researchers argue that 5G will be inadequate in a short time, given the explosive growth of machine connectivity, such as the Internet-of-Things (IoT). This has prompted many to question what comes after 5G. The obvious answer is sixth-generation (6G), however, the substance of 6G is still very much undefined, leaving much to the imagination in terms of real-world implementation. What is clear, however, is that the next generation will likely involve the use of terahertz frequency (0.1–10 THz) electromagnetic waves. Here, we review recent research in terahertz wireless communications and technology, focusing on three broad topic classes: the terahertz channel, terahertz devices, and space-based terahertz system considerations. In all of these, we describe the nature of the research, the specific challenges involved, and current research findings. We conclude by providing a brief perspective on the path forward.

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