Mainz 2026 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 30: QuanTour III – Spin Physics & Coherence
Q 30.7: Talk
Wednesday, March 4, 2026, 16:15–16:30, P 1
Floquet-Engineered Two-Photon Excitation of Biexcitons — •Paul C. A. Hagen1, Jun-Yong Yan3, Moritz Cygorek2, Doris E. Reiter2, Feng Liu3, and Vollrath M. Axt1 — 1TPIII, Universität Bayreuth, Germany — 2CMT, TU Dortmund, Germany — 3Zhejiang University, China
Semiconductor quantum dots (QDs) are promising solid-state platforms for generating on-demand single and entangled photons in quantum technology applications. Two-photon excitation (TPE) is a key technique for creating biexcitons, where two degenerate photons are simultaneously absorbed by a QD to excite it into the biexciton state. We show that this process also occurs when both photons are symmetrically detuned so that their combined energy matches the ground-to-biexciton transition. The excitation becomes most efficient when the detuning exceeds the biexciton binding energy, and a short temporal delay between pulses is introduced. We refer to this approach as Floquet engineered two-photon excitation (FTPE)[1]. FTPE offers concrete advantages over conventional TPE: it is more robust against laser power variations, allows efficient laser filtering, and exhibits both theoretically and experimentally higher excitation efficiency, even in the presence of phonons [1]. Using Floquet theory, we explain its dynamics and demonstrate that stroboscopic models provide an accurate description of the underlying mechanism.
[1] J. Y. Yan, P. C. A. Hagen et al. arXiv: 2504.02753
Keywords: Floquet; Two Photon Excitation; Biexiton