Femtosecond Transfer and Manipulation of Persistent Hot-Trion Coherence in a Single CdSe/ZnSe Quantum Dot

Henzler P, Traum C, Holtkemper M, Nabben D, Erbe M, Reiter DE, Kuhn T, Mahapatra S, Brunner K, Seletskiy DV, Leitenstorfer A

Abstract

Ultrafast transmission changes around the fundamental trion resonance are studied after exciting a p-shell exciton in a negatively charged II-VI quantum dot. The biexcitonic induced absorption reveals quantum beats between hot-trion states at 133GHz. While interband dephasing is dominated by relaxation of the P-shell hole within 390fs, trionic coherence remains stored in the spin system for 85ps due to Pauli blocking of the triplet electron. The complex spectrotemporal evolution of transmission is explained analytically by solving the Maxwell-Liouville equations. Pump and probe polarizations provide full control over amplitude and phase of the quantum beats.