Dresden 2026 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 52: THz and MIR Physics in Semiconductors
HL 52.3: Talk
Friday, March 13, 2026, 10:00–10:15, POT/0006
Plasmonic nonlinearity in AlGaN/GaN-based rectangular patches — •Nandita Bajpai1, Pavlo Sai2,4, Maksym Dub2,4, Alexej Pashkin3, Stephan Winnerl3, Wojciech Knap2,4, and Martin Mittendorff1 — 1Department of Physics, University of Duisbur-Essen,Duisburg,Germany — 2Institute of HighPressurePhysics,Warsaw,Poland — 3Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 4Center for Terahertz Sciences and Applications CENTERA -CEZAMAT Warsaw University of Technology, Warsaw, Poland
Recent observation of enhanced nonlinear THz absorption by resonant excitation of 2D plasmons in the AlGaN/GaN based plasmonic crystal has revealed a strong pump-induced transparency of probe upto 45%[1].Here, we investigate the nonlinear coupling between the perpendicular plasmonic modes in AlGaN/GaN-based rectangular patches. To this end, we performed a two colour pump probe experiment at the free-electron laser facility at the Helmholtz-Zentrum Dresden-Rossendorf. The spectrally narrow pump pulse was used to drive the plasmonic resonance at 1.95 THz whereas a broadband THz pulse from a synchronized table-top time domain spectroscopy setup was exploited to probe the plasmonic mode at 1.38 THz. We observed a relative pump - induced change in transmission of probe upto 12%, which is attributed to the excitation of hot carriers that decays within 25ps.
[1] P.Sai et al., Adv. Optical Matter.2025,13,2500716; https://doi.org/10.1002/adom.202500716
Keywords: Plasmonic oscillations; THz pump-THz probe; Two dimensional electron gas