Relativistic Doppler reflection as a probe for the initial relaxation of a non-equilibrium electron-hole plasma in silicon

Thomson, Mark D.Physikalisches Institut, Goethe-University, D-60438 Frankfurt am Main,Germany (author)

This paper reviews the status of investigations of the relativistic Doppler reflectionof a broadband terahertz pulse at a counter-propagating plasma front of photo-excited chargecarriers in undoped silicon. When a THz pulse with 20-THz bandwidth impinges onto amoving plasma front with a carrier density in the range of 1019 per cm3, one observes a spectralup-shift, which is, however, much less pronounced than expected from simulations assuming a Drude plasma characterized by a single carrier relaxation time τ of the order of 15-100 fs.Qualitative agreement between simulations and experiments can be achieved if τ is chosen tobe less than 5 fs. In order to explore carrier relaxation in more detail, optical-pump/THz-probeexperiments in the conventional co-propagation geometry were performed. If the pump-probedelay is long enough for monitoring of the equilibrium value of the scattering time, τ rangesfrom 200 fs at low carrier density to 20 fs in the 1019-cm-3 density range. For small (subpicosecond)pump-probe delay, the data reveal a significantly faster scattering, which slowsdown during energy relaxation of the charge carriers.

Meng, FanqiPhysikalisches Institut, Goethe-University, D-60438 Frankfurt am am Main, Germany (author)
Sernelius, Bo E.,1948-Linköpings universitet,Teoretisk Fysik,Tekniska fakulteten(Swepub:liu)bose02 (author)
Roskos, Hartmut G.Physikalisches Institut, Goethe-University, D-60438 Frankfurt am Main (author)
Physikalisches Institut, Goethe-University, D-60438 Frankfurt am Main,GermanyPhysikalisches Institut, Goethe-University, D-60438 Frankfurt am am Main, Germany (creator_code:org_t)

In:19th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON'19): Institute of Physics (IOP), s. 012016-012019

By the author/editor: Thomson, Mark D.; Meng, Fanqi; Sernelius, Bo E. ...; Roskos, Hartmut ...

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Physical Science ...; and Condensed Matter ...

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