Optical Excitation of Coherent THz Dynamics of the Rare-Earth Lattice through Resonant Pumping of f-f Electronic Transition in a Complex Perovskite DyFeO_{3}.

Resonant pumping of the electronic f-f transitions in the orbital multiplet of dysprosium ions (Dy^{3+}) in a complex perovskite DyFeO_{3} is shown to impulsively launch THz lattice dynamics corresponding to the B_{2g} phonon mode, which is dominanted by the motion of Dy^{3+} ions. The findings, supported by symmetry analysis and density-functional theory calculations, not only provide a novel route for highly selective excitation of the rare-earth crystal lattices but also establish important relationships between the symmetry of the electronic and lattice excitations in complex oxides.

Reduced Surface Recombination in Extended-Perimeter LEDs toward Electroluminescent Cooling.

III-V semiconductor light-emitting diodes (LEDs) are a promising candidate for demonstrating electroluminescent cooling. However, exceptionally high internal quantum efficiency designs are paramount to achieving this goal. A significant loss mechanism preventing unity internal quantum efficiency in GaAs-based devices is nonradiative surface recombination at the perimeter sidewall.

The Role of Ferromagnetic Layer Thickness and Substrate Material in Spintronic Emitters.

In this article, we investigate optically induced terahertz radiation in ferromagnetic FeCo layers of varying thickness on Si and SiO substrates. Efforts have been made to account for the influence of the substrate on the parameters of the THz radiation generated by the ferromagnetic FeCo film. The study reveals that the thickness of the ferromagnetic layer and the material of the substrate significantly affect the generation efficiency and spectral characteristics of the THz radiation.

Increasing the Efficiency of a Spintronic THz Emitter Based on WSe/FeCo.

We report an increase in terahertz (THz) radiation efficiency due to FeCo/WSe structures in the reflection geometry. This can be attributed to an absorption increase in the alloy FeCo layer at the input FeCo/WSe interface due to constructive interference, as well as to the backward transport of hot carriers from FeCo to WSe. In contrast to the transmission geometry, the THz generation efficiency in the reflection is much less dependent on the magnetic layer thickness.

Polarization control of THz emission using spin-reorientation transition in spintronic heterostructure.

Polarization of electromagnetic waves plays an extremely important role in interaction of radiation with matter. In particular, interaction of polarized waves with ordered matter strongly depends on orientation and symmetry of vibrations of chemical bonds in crystals. In quantum technologies, the polarization of photons is considered as a "degree of freedom", which is one of the main parameters that ensure efficient quantum computing.