Terahertz Research Papers - Academia.edu (original) (raw)

Using time-domain Terahertz spectroscopy we performed direct studies of the photoinduced suppression and recovery of the superconducting gap in a conventional BCS superconductor. Both processes are found to be strongly temperature and... more

Using time-domain Terahertz spectroscopy we performed direct studies of the photoinduced suppression and recovery of the superconducting gap in a conventional BCS superconductor. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the bare recombination rate of quasiparticles, the Cooper pair-breaking rate and the electron-phonon coupling constant, lambda=1.1pm0.1,\lambda=1.1\pm0.1,lambda=1.1pm0.1, which is in excellent agreement with theoretical estimates.

Received July 7, 2010; accepted August 20, 2010; posted August 23, 2010 (Doc. ID 131246); published September 23, 2010 In this paper, a parallel-plate ladder waveguide (PPLWG) is proposed for terahertz waveguiding. A modal analysis of the... more

Received July 7, 2010; accepted August 20, 2010; posted August 23, 2010 (Doc. ID 131246); published September 23, 2010 In this paper, a parallel-plate ladder waveguide (PPLWG) is proposed for terahertz waveguiding. A modal analysis of the proposed ...

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... more

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.

We demonstrate a terahertz flat lens based on tri-layer meta-surfaces allowing for broadband linear polarization conversion , where the phase can be tuned through a full 2π range by tailoring the geometry of the subwavelength resonators.... more

We demonstrate a terahertz flat lens based on tri-layer meta-surfaces allowing for broadband linear polarization conversion , where the phase can be tuned through a full 2π range by tailoring the geometry of the subwavelength resonators. The lens functionality is realized by arranging these resona-tors to create a parabolic spatial phase profile. The fabricated 124-μm-thick device is characterized by scanning the beam profile and cross section, showing diffraction-limited focus-ing and ∼68% overall efficiency at the operating frequency of 400 GHz. This device has potential for applications in terahertz imaging and communications, as well as beam control in general.