In this paper the impact of Shockley-Read-Hole (SRH) recombination on the performance of organic (OSCs) and perovskite (PSCs) solar cells is comparatively analyzed by the drift–diffusion model. It has been established that for OSCs SRH recombination dominantly affects short circuit current ( J_sc ), while for PSCs open circuit voltage ( V_oc ) is mostly affected, both resulting in a significant reduction of efficiency. Considering that one of the fundamental differences between organic materials and perovskites is the mobility of charge carriers, the influence of mobility on the loss of J_sc and V_oc due to SRH recombination in both types of solar cells was investigated. Higher V_oc and J_sc losses were observed in PSCs. The obtained results were explained by analyzing the operation of the devices in short-circuit and open-circuit. Unlike PSCs, in short-circuit of OSCs, a significant amount of charge carriers remains in the active layer. The pronounced SRH recombination appears which reduces the conductivity and therefore the drift current and consequently J_sc . At open circuit, in both OSCs and PSCs, the drift current balances the diffusion current which is found to be independent of SRH recombination. The decrease in conductivity therefore leads to an increase in the electric field, thus lowering V_oc . Obtained results are supported by experimental evidence from literature.
The formation mechanisms of Laser-Induced Periodic Surface Structures (LIPSS) on Nb/Ti multilayer thin films following picosecond laser surface modification were systematically investigated. The multilayers, consisting of fifteen (Nb/Ti) bilayers with a total thickness of 440 nm, were deposited on (100) Si substrates by DC ion sputtering. Dynamic laser patterning in the form of laser-inscribed lines was performed using 15 ps pulses from a Nd:YVO4 laser operating at 355 nm, with pulse energies ranging from 1.5 to 2.8 µJ. By increasing the pulse energy at constant scanning speeds (5 mm s−1 and 1 mm s−1), a sequential evolution of surface morphology was observed: (i) initial melting with cluster formation, (ii) elongation of molten regions and emergence of high-spatial-frequency LIPSS (HSFL), (iii) droplet separation and alignment into low-spatial-frequency LIPSS (LSFL), (iv) sharp boundary formation corresponding to LSFL positions, (v) surface recrystallization, and (vi) material ablation at the highest fluences. Post-irradiation compositional analysis revealed an increased oxygen content in the modified zones compared to the untreated regions, indicating the formation of an ultra-thin oxide layer.
Transparent ceramic laser materials have been extensively studied for high-power laser applications, where scattering loss is a significant factor affecting laser output power. This study presents a method based on an integrating sphere combined with a multipass cell for measuring the scattering and absorption coefficients of laser materials, providing improved measurement precision. Pure YAG and Yb:YAG ceramic samples were investigated and systematically compared with pure YAG and Yb:YAG single crystals with the same Yb3+ doping concentration. Specifically, the scattering coefficients at 1064 nm were measured to be 0.0046 cm−1 for YAG ceramic and 0.0093 cm−1 for Yb:YAG ceramic, while the corresponding absorption coefficients were 0.0267 cm−1 and 0.0221 cm−1, respectively, which are close to those of the single crystals. Furthermore, overall optical quality and wavefront distortion were analyzed using a Shack-Hartmann wavefront sensor. The proposed method increases the effective optical interaction length, enhances the detectable loss signal, and improves measurement reliability, providing a practical approach for characterizing scattering and absorption losses in low-loss laser materials.
We propose a scheme for realizing nonreciprocal bipartite and tripartite entanglement in a hybrid cavity optomagnonic system. The system consists of a tunable Fabry-Perot (FP) cavity and a microwave cavity, an yttrium iron garnet slab (YIG1) and a rotating yttrium iron garnet sphere (YIG2). The magnon modes in both YIG1 and YIG2 are strongly coupled to the microwave cavity mode, and the magnon mode in YIG1 also has a three-mode resonant interaction with the optical modes in the FP cavity. The Barnett effect causes a frequency shift of the magnon mode in YIG2. By reversing the external bias magnetic field of YIG2 to control the sign of the Barnett frequency shift, one can not only switch the entanglement partner of the optical mode between the magnon and microwave modes, but also achieve perfect on-off control of bipartite optical-microwave entanglement and tripartite optical-magnon-microwave entanglement. The study presents a flexible control scheme to realize nonreciprocal bipartite and tripartite entanglement in quantum nodes that integrate diverse physical systems such as optics, magnons, and microwaves, and may have potential applications in entanglement-based quantum networks.
We investigate the differential-reflectance signature of a Fano-type plasmonic response in a reflective plasmonic grating structure. A double-layer Au diffraction grating—designed to operate in contact with ethanol under 780-nm illumination from the analyte side—is fabricated on a sapphire substrate using electron-beam lithography and vacuum deposition. Rigorous coupled-wave analysis reveals an asymmetric reflectance peak with steep angular variation, while numerical differentiation of the reflectance spectrum produces a sharp differential reflectance dip. Reflectance mapping combined with Rayleigh anomaly and propagating surface plasmon dispersion relations, along with quantitative near-field analysis, indicates that the observed response is consistent with a Fano-type plasmonic response involving localized and propagating plasmonic components. Angular reflectance measurements reproduce both the asymmetric reflectance peak and differential reflectance dip, in good agreement with the simulations. The potential sensing performance is evaluated from the simulated refractive-index sensitivity and experimentally obtained linewidth. These results demonstrate that differential reflectance provides a useful readout of a Fano-type plasmonic response in reflective plasmonic grating sensors, particularly for low-refractive-index liquids.
