Publications (2)3.4 Total impact
-
Article: Excitation-density-dependent generation of broadband terahertz radiation in an asymmetrically excited photoconductive antenna.
[show abstract] [hide abstract]
ABSTRACT: The generation of terahertz (THz) transients in photoconductive emitters has been studied by varying the spatial extent and density of the optically excited photocarriers in asymmetrically excited, biased low-temperature-grown GaAs antenna structures. We find a pronounced dependence of the THz pulse intensity and broadband (>6.0 THz) spectral distribution on the pump excitation density and simulate this with a three-dimensional carrier dynamics model. We attribute the observed variation in THz emission to changes in the strength of the screening field.Optics Letters 08/2007; 32(16):2297-9. · 3.40 Impact Factor -
Article: Emission of collimated THz pulses from photo-excited semiconductors
[show abstract] [hide abstract]
ABSTRACT: It is shown experimentally that surface-field terahertz (THz) emitters can produce well-collimated beams of THz radiation, making them useful devices for time-domain spectroscopy applications. Simulations of the carrier-dynamics are used to explain the mechanism of THz generation in InAs and GaAs, and it is shown that inter-valley scattering of electrons must be considered in order to fully describe THz emission from InAs.