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HL: Fachverband Halbleiterphysik
HL 52: THz and MIR Physics in Semiconductors
HL 52.2: Vortrag
Freitag, 13. März 2026, 09:45–10:00, POT/0006
AlGaN/GaN-based grating-gate plasmonic crystals for nonlinear THz applications — Pavlo Sai1, Vadym V. Korotyeyev2, Serhii Kukhtaruk2, Dmytro B. But1, Maksym Dub1, Alexej Pashkin3, Stephan Winnerl3, Wojciech Knap1, and •Martin Mittendorff4 — 1Institute of High Pressure Physics PAS ul. Sokołowska 29/37, Warsaw 01-142, Poland — 2V. Ye. Lashkaryov Institute of Semiconductor Physics (ISP) NASU prospect Nauky 41, Kyiv 03028, Ukraine — 3Helmholtz-Zentrum Dresden-Rossendorf 01328 Dresden, Germany — 4Universität Duisburg-Essen Fakultät für Physik 47057 Duisburg, Germany
We present time-resolved THz measurements on grating-gate plasmonic crystals, based on the two-dimensional interface electron gas in epitaxial GaN/AlGaN heterostructures. The free-electron laser FELBE at Helmholtz-Zentrum Dresden-Rossendorf served as tunable source for intense, narrowband THz pulses at about 1.8 THz, the plasmon frequency was tuned via the grating-gate. The strongest pump-probe signals are observed at resonance, where a rather low pump fluence of about 200 nJ/cm2 leads to a pump-induced change in transmission of more than 40% [1]. The signal decays within about 50 ps. The experimental results are complemented by a finite-difference time-domain electrodynamic simulation, allowing to identify the main driving mechanisms for the observed strong nonlinearity, e.g. near-field effects and hot charge carriers.
[1] P. Sai et al., Adv. Optical Mater. 2025, 13, 2500716; https://doi.org/10.1002/adom.202500716
Keywords: AlGaN/GaN; THz nonlinearity; THz plasmonics