Browsing by Author "Elsaesser, T"

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Nonlinear terahertz spectroscopy of semiconductor nanostructures
(2004-03-01)
Luo, C
;
Reimann, K
;
Woerner, M
;
Elsaesser, T
;
電子物理學系
Nonlinear frequency conversion and electro-optic sampling allow for the generation and phase-resolved characterization of few-cycle pulses in the frequency range up to 50 THz. Electric field transients with amplitudes of up to several MV/cm are applied to study coherent nonlinear excitations of low-dimensional semiconductors. We report the first observation of Rabi oscillations on intersubband transitions of electrons in GaAs/AlGaAs quantum wells. Frequency and phase of such oscillations are controlled in the 0.3- to 2.5-THz range via the strength and shape of the mid-infrared driving pulse.
Phase-resolved nonlinear response of a two-dimensional electron gas under femtosecond intersubband excitation
(2004-01-30)
Luo, CW
;
Reimann, K
;
Woerner, M
;
Elsaesser, T
;
Hey, R
Strong electric-field transients resonant to intersubband transitions in n-type modulation-doped GaAs/AlGaAs quantum wells induce coherent Rabi oscillations, which are demonstrated by a phase-resolved measurement of the light emitted by the sample. The time evolution of the intersubband polarization is influenced by Coulomb-mediated many-body effects. The subpicosecond period and the phase of the Rabi oscillations are controlled by the properties of the midinfrared driving pulse.