Terahertz Plasmonics

The first demonstration of THz amplification by graphene nanostructures achieved by RIEC-Sendai-Tohoku University team[1,2] raised many fundamental questions like : i) is the graphene really necessary ii) can one scale results obtained on sub-wavelength (μm scale) graphene flakes up to practical size (mm scale) THz amplifier devices. In this work we present recent results on GaN/AlGaN based plasmonic structures obtained in CENTERA -Warsaw, showing that in moderate cryogenic conditions (temperatures ~80K) in many aspects (i.e. carrier density, mobility and optical phonon energy) these structures mimic graphene nanostructures used in the first amplification experiments. The results allow us to identify main challenges/difficulties on the way towards realistic (practical size) plasmonic amplifiers of THz radiation [3,4,5].

ACKNOWLEDGMENTS
Funded by the European Union (ERC ADAVANCED PROJECT -TERAPLASM #101053716). The work was also supported by the “International Research Agendas” Projects CENTERA &CENTERA2 of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund (Grant No. MAB/2018/9 for CENTERA & FENG.02.01-IP.05-T004/23) for CENTERA2).

REFERENCES

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   Electrical Tuning of Terahertz Plasmonic Crystal Phases
   Phys. Rev. X 13, 041003, Published : 04 October 2023
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   THz Properties of Grating-Gate Plasmonic Crystals
   Lithuanian Journal of Physics Vol. 63, No. 4, pp. 251–263 (2023), Published : 15 December 2023
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   Plasmons in AlGaN/GaN grating-gate structure probing with 300 K background illumination
   AIP Advances 13, 095017 (2023), Published online: 19 September 2023

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