73 citations · 455 across the 28 of their papers we have counts for
16 papers · 1 filter
Contact-free charge carrier density determination of doped sub-μm thin cubic GaN layers with terahertz time-domain spectroscopy
Joshua Hennig, Mario F. Zscherp, Silas A. Jentsch +11
As cubic GaN is a promising material for optoelectronic applications, its layers need to be precisely doped to realize the desired properties. While contact-based methods are estab…
Mach-Zehnder based Rotational Shearing Interferometer for Non-destructive Testing using Spatial Phase-Shifting Shearography
Valentin-Johannes Bastgen, Michael Schuth, Georg von Freymann
This work introduces a novel optical setup based on a Mach-Zehnder interferometer, enabling spatial phase shifting shearography with rotational shear. The optical concept employs a…
Spatiotemporal Terahertz Emission Nanoscopy of Spintronic Photocurrents
F. Paries, R. Rouzegar, J. Cai +9
Capturing ultrafast spin and charge photocurrents on nanoscopic scales is essential for fundamental research in physics and engineering, as well as for future applications, such as…
Wide-range resistivity characterization of semiconductors with terahertz time-domain spectroscopy
Joshua Hennig, Jens Klier, Stefan Duran +9
Resistivity is one of the most important characteristics in the semiconductor industry. The most common way to measure resistivity is the four-point probe method, which requires ph…
Broadband mode division multiplexing of OAM-modes by a micro printed waveguide structure
Julian Schulz, Georg von Freymann
A light beam carrying orbital angular momentum (OAM) is characterized by a helical phase-front that winds around the center of the beam. These beams have unique properties that hav…
Mixing Rule for Calculating the Effective Refractive Index Beyond the Limit of Small Particles
Dominic T. Meiers, Georg von Freymann
Considering light transport in disordered media, the medium is often treated as an effective medium requiring accurate evaluation of an effective refractive index. Because of its s…
Fiber-tip spintronic terahertz emitters
Felix Paries, Nicolas Tiercelin, Geoffrey Lezier +12
Spintronic terahertz emitters promise terahertz sources with an unmatched broad frequency bandwidth that are easy to fabricate and operate, and therefore easy to scale at low cost.…
Initiator-free photo-crosslinkable cellulose-based resists for fabricating submicron patterns via direct laser writing
Maximilian Rothammer, Dominic T. Meiers, Maximilian Maier +2
Novel bifunctional cellulose diacetate derivatives were synthesized in order to achieve bio-based photoresists, which can be structured by two-photon absorption via direct laser wr…
Electronic Phase Detection with sub-10 fs Timing Jitter for Terahertz Time-Domain Spectroscopy Systems
Felix Paries, Oliver Boidol, Georg von Freymann +1
Terahertz time-domain spectroscopy systems based on resonator-internal repetition-rate modulation, such as SLAPCOPS [12] and ECOPS [11], rely on electronic phase detectors which ar…
Towards efficient structure prediction and pre-compensation in multi-photon lithography
Nicolas Lang, Sven Enns, Julian Hering +1
Microscale 3D printing technologies have been of increasing interest in industry and research for several years. Unfortunately, the fabricated structures always deviate from the re…
Photonic quadrupole topological insulator using orbital-induced synthetic flux
Julian Schulz, Jiho Noh, Wladimir A. Benalcazar +2
The rich physical properties of multiatomic molecules and crystalline structures are determined, to a significant extent, by the underlying geometry and connectivity of atomic orbi…
Observation of Quadratic (Charge-2) Weyl Point Splitting in Near-Infrared Photonic Crystals
Christina Jörg, Sachin Vaidya, Jiho Noh +4
Weyl points are point degeneracies that occur in momentum space of periodic materials, and are associated with a quantized topological charge. We experimentally observe in a 3D mic…
Existence of a negative next-nearest-neighbor coupling in evanescently coupled dielectric waveguides
Julian Schulz, Christina Jörg, Georg von Freymann
We experimentally demonstrate that the next-nearest-neighbor(NNN)coupling in an array of waveguides can naturally be negative. To do so, dielectric zig-zag shaped waveguide arrays…
Observation of bound states in the continuum embedded in symmetry bandgaps
Alexander Cerjan, Christina Jörg, Sachin Vaidya +5
In the last decade, symmetry-protected bound states in the continuum (BICs) have proven to be an important design principle for creating and enhancing devices reliant upon states w…
Dynamic defects in photonic Floquet topological insulators
Christina Jörg, Fabian Letscher, Michael Fleischhauer +1
Edge modes in topological insulators are known to be robust against defects. We investigate if this also holds true when the defect is not static, but varies in time. We study the…
Negative-index bi-anisotropic photonic metamaterial fabricated by direct laser writing and silver shadow evaporation
Michael S. Rill, Christine Plet, Michael Thiel +3
We present the blueprint for a novel negative-index metamaterial. This structure is fabricated via three-dimensional two-photon direct laser writing and silver shadow evaporation.…