Gabriel Hein

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We present a THz investigation of histo-pathological samples including the larynx of a pig and a human liver with metastasis. Our measurements show that different types of tissue can be clearly distinguished in THz transmission images, either within a single image or by a comparison of images obtained for different frequency windows. This leads to the(More)
The preparation of quantum Hall effect device arrays at the PTB using multiterminal connections has been improved by the use of SiO<sub>2</sub> as insulation material for the multilayer connections. The used lay-out avoids connections crossing the active sections of the devices. Arrays with ten devices in series as well as in parallel have been realised and(More)
The EnviSat altimeter, RA-2, is intended to continue an uninterrupted series of measurements of sea-level and ice-sheet elevation started by ERS-1 in 1991. To fully exploit these measurements, an absolute reference in the time series, and a distinction between instrumental artifacts and significant geophysical signals, is necessary. Therefore, the range(More)
We study growth and magnetotransport properties of Ga(Al)As based asymmetric double two-dimensional electron gases (2DEG) consisting of a quantum well stacked on top of a heterojunction. We show that the electron densities of the two parallel 2DEG channels can be reliably matched by variation of a single growth parameter. Metrological quality of the(More)
We introduce a novel optoelectronic technique for the characterization of the full step response of ultrafast sampling oscilloscopes. The uncertainty of the step response measurement is derived from a Monte-Carlo analysis. The enhanced experimental and theoretical method allows us to specify the rise-time of the step response with a considerably reduced(More)
Different batches of quantum Hall samples are produced by PTB within the European project "AC Quantum Hall". The AC characterization of the samples by IEN is part of the same project. For each device, the parasitic effects are analyzed by measuring the resistive and reactive components of the longitudinal impedance. First results are shown as examples.
We present a novel four-electrode photoconductive switch which allows us to modify the photocurrent and the THz emission spectrum. These effects result from an appropriately chosen inhomogeneous electric field applied across the non-uniform carrier distribution.
In this work we present a novel, inductance-based system to measure and control the motion of bellows-driven continuum joints in soft robots. The sensing system relies on coils of wire wrapped around the minor diameters of each bellows on the joint. As the bellows extend, these coils of wire become more distant, decreasing their mutual inductance. Measuring(More)