Echo behavior in ruby

Peer reviewedElectrical and Computer Engineerin

Adiabatic compression of terahertz waves using metal flares

We report on the adiabatic free-space coupling of broadband terahertz (THz) radiation through a subwavelength gap using metal flares. Amplitude coupling ratios better than 30% are obtained by optimizing the curvature. This scheme shows a large potential for increasing the sensitivity in THz spectroscopy using high spatial confinement without the need of transmission optics or high precision components. The intrinsic curvature of metal sheets is already sufficient to carry out experiments downsizing the microwave approach.Peer reviewedElectrical and Computer Engineerin

Integrated waveguide-coupled terahertz microcavity resonators

We demonstrate integrated square terahertz microcavity resonators side coupled to waveguides. We present the microcavity transmission spectra for different resonator sizes and coupling strengths. The measured quality factors due to external coupling and cavity loss are found to be between 40 and 90 and between 30 and 40, respectively, for cavity resonance frequencies between 1.077 and 1.331 THz.Peer reviewedElectrical and Computer Engineerin

Capacitance free generation and detection of subpicosecond electrical pulses on coplanar transmission lines

Based on a reanalysis of previous work and new experimental measurements, we conclude that the parasitic capacitance at the generation site is negligible for sliding contact excitation of small dimension coplanar transmission lines.Peer reviewedElectrical and Computer Engineerin

Adiabatic Coupling into Terahertz Parallel-Plate Waveguides

Abstract We report on the coupling process of broadband terahertz radiation into metal parallel-plate waveguides with sub-wavelength gaps. Starting from well known quasi-optic coupling using silicon lenses, we developed a coupling scheme based on adiabatic coupling using metal flares. The metal surfaces change their shape slowly and smoothly with respect to the wavelength of terahertz radiation (300 µm). The undistorted pulse shape and dispersion-free propagation is maintained in the TEM geometry. The obtained coupling efficiencies for different waveguide geometries exceed previous values. For an optimized layout, also spectroscopic results of polycrystalline molecular samples are presented revealing high resolution absorption lines