Berlin 2012 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena

HL 43.27: Poster

Dienstag, 27. März 2012, 09:30–12:30, Poster D

Optical excitation of squeezed LO phonons in a quantum well — •Thomas Papenkort¹, Vollrath Martin Axt², and Tilmann Kuhn¹ — ¹Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — ²Institut für Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany

Squeezed states combine questions of fundamental quantum mechanics with the promise of a precision of measurements that was previously deemed impossible to achieve. With squeezed light fields this promise has already been achieved, and it is only natural to try to carry over these huge successes to the field of solid state physics: that is, to learn how to generate squeezed phonon states in crystals.

In this contribution we present quantum-kinetic simulations showing how to generate squeezed phonon states in a quantum well by optical driving. In such states the uncertainty of the lattice displacement or momentum is reduced below its zero-temperature value. We demonstrate how to calculate the coupled electron-phonon dynamics within a realistic microscopic model of a quantum well, achieving quantitative results for, e.g., the squeezing factor. We fully take into account spatial averaging, which is both unavoidable experimentally and crucial for the lattice uncertainty variables. Our simulations then reveal which ultrashort laser excitations are capable of generating squeezed states and predict the strength and time-dependence of the squeezing factor.