Ultrafast photon drag detector for intersubband spectroscopy
نویسنده
چکیده
The photon drag effect of a 2D electron gas is measured using the ps infrared pulses of the wavelength-tunable free electron laser source FELIX. The pulsed photon drag response is found to depend critically on the coupling characteristics of the electrical circuit. We therefore developed an impedance and velocity matched photon drag detector. It consists of a GaAs/ AlGaAs multi quantum well sample which forms an integral part of a microstrip line. A Ge-prism enables incoupling at the critical total reflection angle. This novel transmission line integrated photon drag detector (TIP-detector) generates signal transients below 10 ps rise and fall times. Its continuous spectral response through the intersubband resonance is investigated at room temperature and at T\100 K. An analysis of the spectral lineshape of the photon drag current response yields information about the momentum relaxation times of the electrons in the ground and excited subbands. ( 1996 Academic Press Limited
منابع مشابه
Direct observation of dynamical screening of the intersubband resonance
We have studied the intersubband resonance of GaAs=AlGaAs multi-quantum well systems by comparing photon drag and absorption spectra. The peak absorption at room temperature is found to be blueshifted from the photon drag resonance by as much as 33 cm−1. We argue that this di erence gives directly the depolarization shift. ? 2000 Elsevier Science B.V. All rights reserved.
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