Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 8: Ultrafast Phenomena I
HL 8.6: Vortrag
Montag, 18. März 2024, 16:30–16:45, EW 015
Ultrahigh-Sensitive Optical Detection of Coherent Acoustic Phonons in a GaAs/GaAlAs Superlattice — •Marek Karzel1, Anton Samusev1, Alexey V. Scherbakov1, Tetiana Linnik1, Mario Littmann2, Andrey V. Akimov3, Dirk Reuter2, and Manfred Bayer1 — 1Technische Universität Dortmund, 44227 Dortmund, Germany — 2Universität Paderborn, 33098 Paderborn, Germany — 3University of Nottingham, NG7 2RD Nottingham, United Kingdom
The optical detection of coherent acoustic phonons is a primary tool in ultrafast acoustics. It engages the application of phonons in quantum technology, which is especially promising for nanoscale communications. The ultrahigh-sensitive detection of optically generated phonons with frequencies above 20 GHz can be accomplished due to optical probing in the spectral vicinity of polariton resonance, where a strong permittivity dispersion is observed [1, 2]. In this work, we monitor the propagation of the optically generated coherent phonon wave packet in a semiconductor superlattice of GaAs/Ga0.67Al0.33As at a temperature of 10 K. With the experimental scheme, we achieve a remarkably high detection sensitivity confirmed by probing coherent acoustic wave packets with less than (on average) one phonon within the bandwidth of interest. The lattice strain induced by such a weak elastic perturbation is of an order of 10−9 with the corresponding lattice displacement of only ≈ 10−16 m.
[1] A. N. Poddubny, et al., Phys. Rev. B 89, 235313 (2014).
[2] M. Kobecki, et al., Phys. Rev. Lett. 128, 157401 (2022).
Keywords: acoustic phonons; polaritons; photoelastic effect; pump-probe spectroscopy; superlattice