Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 89: Quantum Dots and Wires: Lasing
HL 89.5: Vortrag
Donnerstag, 10. März 2016, 17:15–17:30, H13
Pump-probe quantum state tomography in quantum-dot amplifiers: Theory and experiment — •Fabian Böhm1, Nicolai B. Grosse1, Nina Owschimikow1, Roland Aust2, Benjamin Lingnau2, Mirco Kolarczik1, Kathy Lüdge2, and Ulrike Woggon1 — 1Institut für Optik und Atomare Physik, Technische Universität Berlin, Germany — 2Institut für Theoretische Physik, Technische Universität Berlin, Germany
Optical quantum state tomography is a method which allows to reconstruct a quantum state by obtaining it's corresponding Wigner function. It can be used to infer the state's density matrix and thus the full quantum information such as the photon number distribution or correlation function can be obtained. We apply this technique to an In(Ga)As quantum-dot optical amplifier and investigate how the coherent state of an ultrashort probe pulse tuned to the quantum dot ground state is transformed by passing through the device. Combination with a probe pulse tuned to the excited state gives access to the dynamics of population inversion and device gain on a sub-picosecond scale as well as the amplified and spontaneous emission noise relative to the quantum noise limit in the amplifier. We experimentally study depletion and recovery mechanisms in the population inversion for varying pump currents and compare them with predictions from a theoretical model for semiconductor amplifiers.