Effective mitigation of photodarkening-induced transverse mode instability in a monolithic fiber laser oscillator by 450 nm laser irradiation.

The photodarkening (PD) and transverse mode instability (TMI) effects are two main factors limiting the power increase and long-term stability of high-power fiber lasers. A prolonged burn-in test for an all-fiber laser oscillator below the TMI threshold was carried out. We observed the PD-induced TMI effects, which manifested as a sudden decrease in the output power due to higher-order mode leakage.

Revealing the influence of doping elements (Ge, Sn, Ca, and Sr) on the properties of α-CsPbI: a DFT investigation.

In this study, using density functional theory, we calculated the band structure and photoelectric properties in a series of 12.5% B-doped (B = Ge, Sn, Ca, and Sr) CsPbI perovskite systems. It is found that Ge doping can improve the structural stability and is more conducive to applications under high-pressure or by applying stress via calculating the bond length, formation energy, elastic properties, and electronic local function.

Influence of Sr doping on the photoelectronic properties of CsPbX (X = Cl, Br, or I): a DFT investigation.

To broaden the application of cesium lead halide perovskites, doping technology has been widely proposed. In this study, we calculated a 12.5% concentration of a Sr-doped CsPbX (X = Cl, Br, or I) perovskite density functional theory.

Electronic Structures and Photoelectric Properties in CsSbX (X = Cl, Br, or I) under High Pressure: A First Principles Study.

Lead-free perovskites of CsSbX (X = Cl, Br, or I) have attracted wide attention owing to their low toxicity. High pressure is an effective and reversible method to tune bandgap without changing the chemical composition. Here, the structural and photoelectric properties of CsSbX under high pressure were theoretically studied by using the density functional theory.

Strain-induced bandgap engineering in CsGeX (X = I, Br or Cl) perovskites: insights from first-principles calculations.

Based on density functional theory and following first-principles methods, this paper investigated the electronic structures, densities of states, effective masses of electrons and holes, and optical properties of CsGeX (X = I, Br or Cl) perovskites under triaxial strains of -4% to 4%. The calculated results show that the tuning range of the bandgaps of the CsGeI, CsGeBr, and CsGeCl perovskites are 1.16 eV, 1.

Dimension-Dependent Bandgap Narrowing and Metallization in Lead-Free Halide Perovskite CsBiX (X = I, Br, and Cl) under High Pressure.

Low-toxicity, air-stable cesium bismuth iodide CsBiX (X = I, Br, and Cl) perovskites are gaining substantial attention owing to their excellent potential in photoelectric and photovoltaic applications. In this work, the lattice constants, band structures, density of states, and optical properties of the CsBiX under high pressure perovskites are theoretically studied using the density functional theory. The calculated results show that the changes in the bandgap of the zero-dimensional CsBiI, one-dimensional CsBiCl, and two-dimensional CsBiBr perovskites are 3.

Structural and Optoelectronic Properties of Two-Dimensional Ruddlesden-Popper Hybrid Perovskite CsSnBr.

Ultrathin inorganic halogenated perovskites have attracted attention owing to their excellent photoelectric properties. In this work, we designed two types of Ruddlesden-Popper hybrid perovskites, CsSnBr and CsSnBr, and studied their band structures and band gaps as a function of the number of layers ( = 1-5). The calculation results show that CsSnBr has a direct bandgap while the bandgap of CsSnBr can be altered from indirect to direct, induced by the 5-Sn state.