A5064083133- Photorefractive and Nonlinear Optics
- Photonic and Optical Devices
- Optical and Acousto-Optic Technologies
- Ferroelectric and Piezoelectric Materials
- Optical Coatings and Gratings
- Solid State Laser Technologies
- Solid-state spectroscopy and crystallography
- Magneto-Optical Properties and Applications
- Blockchain Technology Applications and Security
- Advanced Fiber Laser Technologies
- Distributed systems and fault tolerance
- Acoustic Wave Resonator Technologies
- Crystal Structures and Properties
- Caching and Content Delivery
Osnabrück University
1990-2023
Since the introduction of first cryptocurrency, Bitcoin, in 2008, gain popularity distributed ledger technologies (DLTs) has led to an increasing demand and, consequently, a larger number network participants general. Scaling blockchain-based solutions cope with several thousand transactions per second or growing nodes always been desirable goal for most developers. Enabling these performance metrics can lead further acceptance DLTs and even faster systems With directed acyclic graphs (DAGs)...
${\mathrm{Sr}}_{0.61}$${\mathrm{Ba}}_{0.39}$${\mathrm{Nb}}_{2}$${\mathrm{O}}_{6}$:Ce exhibits pronounced dichroism which is strongly correlated with the cerium concentration. This property triggers effective hologram recording mutually orthogonal polarized writing beams via self-diffraction. We measure saturation diffraction efficiency, using an extraordinarily readout beam, versus polarization of beams. The experimental results are compared to straightforward theoretical models based on...
If an elementary hologram with grating vector K is recorded in a photosensitive material, the complex refractive index modulated same spatial frequency K. A beam-coupling measurement proper tool for simultaneous investigation of absorption and refractive-index grating, which correspond to imaginary real parts modulation, respectively. Using analysis makes it possible determine magnitude as well their phase shift respect writing intensity pattern, one single-beam-coupling measurement. The...
Abstract Beam-coupling topography is a non-destructive holographic technique for spatially resolved recording of hysteresis loops and imaging domains. Its basic principle interference rays diffracted from grating with collinear, transmitted ones. Full domain contrast noise suppression achieved by appropriate control intensity phase the interfering beams. The method applied to antiparallel a-domains in (Sr0.61Ba0.39)Nb2O6:Ce.
Beam-coupling topography is a new holographic technique for spatially resolved studies of induced and spontaneous polarization in photorefractive crystals. It especially suited mapping 180°-domains. In this paper theoretical experimental fundamentals the method are outlined. Some results on Ba0.29Sr0.71Nb2O6:Ce given.
A new holographic observation technique for 180° domains is demonstrated with a cerium-doped strontium barium niobate sample containing two antiparallel ferroelectric domains. The method relies on the fact that phase shift of holographically written refractive-index gratings +π/2 or -π/2 respect to initial light interference pattern depending orientation As consequence, readout these creates at exit face patterns shifted by 0 π one. These patterns, providing an image domain structure, are...
The mechanism of the photorefractive effect in ${\mathrm{Cd}}_{13}$${\mathrm{P}}_{4}$${\mathrm{S}}_{22}$${\mathrm{I}}_{2}$ (CPSI) has been investigated with holographic methods. Our experimental results reveal that properties CPSI do not originate from electro-optic but a different type mechanism, probably light-induced ionic transport process.