Temperature Dependence Of Spectral Properties Research Articles

Temperature Dependence of Spectral Properties of Yb-Doped Superfluorescent Fiber Source

Temperature Dependence of Spectral Properties of Yb-Doped Superfluorescent Fiber Source

Preparation, structure and temperature dependence of spectral properties of Yb3+/Er3+ doped Sr5(PO4)3F transparent glass ceramics

The Sr5(PO4)3F transparent glass ceramics (GCs) were achieved for the first time by crystallizing from low-cost lead-free borate glasses. The structure, optical and Up-conversion luminescence characteristics of Yb3+/Er3+ co-doped transparent GCs were studied. The results show that the luminescence properties of Sr5(PO4)3F transparent GCs are distinctly improved compared with precursor glass, which stands to benefit from both low phonon energy environment of Sr5(PO4)3F GCs and the unique structural features of fluorapatite. Under the 980 nm laser, the optical temperature measurement performance of GC samples was evaluated based on the fluorescence intensity ratio by using thermal coupling energy level of Er3+ ion. In this wide temperature range from 303 K to 653 K, the maximum relative sensitivity and maximum absolute sensitivity obtained are 1.26% K−1 and 0.31% K−1, respectively. It is expected to be applied in the field of optical temperature sensing.

Normal state electronic properties of [formula omitted] superconductors

A good description of the electronic structure of BiS2-based superconductors is essential to understand their phase diagram, normal state and superconducting properties. To describe the first reports of normal state electronic structure features from angle resolved photoemission spectroscopy (ARPES) in LaO1−xFxBiS2, we used a minimal microscopic model to study their low energy properties. It includes the two effective tight-binding bands proposed by Usui et al., Phys. Rev. B, 86, 2012, 220501(R), and we added moderate intra- and inter-orbital electron correlations related to Bi-(pY, pX) and S-(pY, pX) orbitals. We calculated the electron Green's functions using their equations of motion, which we decoupled in second-order of perturbations on the correlations. We determined the normal state spectral density function and total density of states for LaO1−xFxBiS2, focusing on the description of the k-dependence, effect of doping, and the prediction of the temperature dependence of spectral properties. Including moderate electron correlations, improves the description of the few experimental ARPES and soft X-ray photoemission data available for LaO1−xFxBiS2. Our analytical approximation enabled us to calculate the spectral density around the conduction band minimum at k→0=(0.45π,0.45π), and to predict the temperature dependence of the spectral properties at different BZ points, which might be verified by temperature-dependent ARPES.