TY  - JOUR
A1  - Klatt, Gregor
A1  - Hilser, Florian
A1  - Qiao, Wenchao
A1  - Beck, Matthias
A1  - Gebs, Raphael
A1  - Bartels, Albrecht
A1  - Huska, Klaus
A1  - Lemmer, Uli
A1  - Bastian, Georg
A1  - Johnston, Michael B.
A1  - Fischer, Milan
A1  - Faist, Jerome
A1  - Dekorsy, Thomas
T1  - Terahertz emission from lateral photo-Dember currents
T2  - Optics Express
N2  - The photo-Dember effect is a source of impulsive THz emission following femtosecond pulsed optical excitation. This emission results from the ultrafast spatial separation of electron-hole pairs in strong carrier gradients due to their different diffusion coefficients. The associated time dependent polarization is oriented perpendicular to the excited surface which is inaptly for efficient out coupling of THz radiation. We propose a scheme for generating strong carrier gradients parallel to the excited surface. The resulting photo-Dember currents are oriented in the same direction and emit THz radiation into the favorable direction perpendicular to the surface. This effect is demonstrated for GaAs and In(0.53)Ga(0.47)As. Surprisingly the photo-Dember THz emitters provide higher bandwidth than photoconductive emitters. Multiplexing of phase coherent photo-Dember currents by periodically tailoring the photoexcited spatial carrier distribution gives rise to a strongly enhanced THz emission, which reaches electric field amplitudes comparable to a high-efficiency externally biased photoconductive emitter.
KW  - Spektroskopie
KW  - Terahertzbereich
KW  - ultrafast processes in condensed matter
KW  - including semiconductors
KW  - spectroscopy
KW  - terahertz
Y1  - 2010
UR  - https://hst.opus.hbz-nrw.de/frontdoor/index/index/docId/145
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:tr5-1457
VL  - 18
IS  - 5
SP  - 4939
EP  - 4947
PB  - OSA
ER  -