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HL: Halbleiterphysik

HL 12: Poster I

HL 12.20: Poster

Montag, 8. März 2004, 16:30–19:00, Poster A

Femtosecond control of electronic motion in semiconductor double quantum wells — •Alex Matos-Abiague und Jamal Berakdar — Max-Planck-Institut für

The quantum dynamics and emission properties of a Al_x Ga_1−xAs based symmetric double quantum well driven by a train of ultrashort half-cycle electromagnetic pulses. By numerically solving the time-dependent Schrödinger equation it is shown that an appropriate design of the train of pulses allows to control the electron motion on a sub-picosecond scale and to achieve and maintain a predefined final electron state. It is also shown that the emission spectrum can be designed by appropriately choosing the parameters of the pulses. The effects of absence of generalized parity of the Floquet modes on the dynamics of the system are discussed. Phenomena such as coherent suppression of tunnelling in absence of accidental degeneration of the quasienergies, low-frequency generation and half harmonic generation are observed. A simplified analytical model that reproduces the main features of the numerical calculations is presented and is utilized to derive simple relations for the values of the pulse parameters that optimize the control process of the electron motion and its emission spectrum.