Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 29: Poster II
HL 29.26: Poster
Dienstag, 18. März 2025, 18:00–20:00, P1
Analytical Theory Of Third Harmonic Generation In Two-Dimensional Materials — •Shridhar Sanjay Shanbhag1, Florentine Friedrich2, Paul Herrmann2, Giancarlo Soavi2,3, and Jan Wilhelm1 — 1Institute of Theoretical Physics and Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, 93053 Regensburg, Germany — 2Institute of Solid State Physics, Friedrich Schiller University Jena, 07743 Jena, Germany — 3Abbe Center of Photonics, Friedrich Schiller University Jena, 07745 Jena, Germany
Valleytronics explores the valley degree of freedom in materials like transition metal dichalcogenides, using electrons in *K valleys as binary states for information encoding. In valleytronics, efficient valley readout is crucial, and third harmonic generation (THG) could provide an ultrafast solution to valley readout for any material, regardless of inversion symmetry.
We derived an analytical expression for THG by solving the semiconductor Bloch equations perturbatively to obtain an expression for the polarization state of the outgoing third harmonic. Our compact expression reveals how material parameters influence the polarization and attributes polarization rotation to valley-dependent optical Stark and Bloch-Siegert shifts. Our theoretical predictions closely align with experiments, providing the microscopic mechanism and thus helping to advancing valleytronic readout mechanisms.
Keywords: TMD; Valleytronics; nonlinear; ultrafast; THG