Wang Tian-Yu,Yang Wei,Hui Hao-Hao,Lei Xiang-Yang,Zhang Qing-Hua,Wang Jian,Xu Qiao,Deng Xue-Ran
The sol–gel method is an important process for the preparation of laser frequency conversion components, such as dihydrogen phosphate (KDP), which are often employed in high-power laser facility. Methyltriethoxysilane (MTS) precursor is a typical matrix to prepare polysiloxane under hydrolysis and polycondensation process. Further coating and curing procedure is applied to obtain desired polysiloxane coating which acts as the moisture-proof and refractive index matching layer. Subsequently, an antireflective coating is prepared over this polysiloxane coating (a bilayer coating system) to realize ultrahigh transmission at desired wavelengths. Due to the low curing temperature (limited by the phase transition temperature of KDP), current MTS-polysiloxane coating could not be completely cured and inter-coating permeation between this bilayer coating system would lead to deterioration of coating properties. Thus, copolymerization of MTS and tetraethylorthosilicate (TEOS) is adopted to fabricate the polysiloxane coating with improved curing property (denser structure and higher hardness after curing). It is found that under certain molar ratio of MTS to TEOS, the structure of modified polysiloxane coating could be effectively densified and the coating hardness increases significantly. Meanwhile, the bilayer coating system still exhibits excellent transmission, high laser-induced damage threshold as well as satisfactory moisture resistance.
Fluoro-sulfo-phosphate (FPS) glass is of current interest as potential material for laser application due to its good glass-forming ability, thermal, and chemical stability as well as the complicated local environment for incorporated species. Herein, the physical and luminescent properties of Er 3+ and Yb 3+ /Er 3+ -doped FPS glasses vs S/F ratio are investigated comprehensively. The low melting temperature (750°C) leads to fewer ingredients evaporation and easier operation. The sulfate addition depolymerizes the structure of FPS glasses, leading to either monotonic or nonmonotonic variations of physical properties, while no deterioration in thermal and limited one in chemical stability is caused. The addition of sulfate also modifies the local structure around optical active species and thus, leading to higher emission cross section (1.52 × 10 −20 cm 2 ), effective linewidth (68.4 nm), figure of merit (5.61 × 10 −23 s cm 2 ), gain bandwidth (102.44 × 10 −27 cm 3 ), and energy-transfer microparameters (51.87 × 10 −39 cm 6 /s), implying high possibility to serve as 1.5 μm laser application.
Yi Yu,Chonghui Niu,Kai Shao,Mingjie Dan,Zhibin Wang,Yingying Wang,Jie Chen,Jiani Luo
A Ho 3+ :KBGM crystal with good quality and large size was successfully grown via TSSG method. The crystal’s structure, ambient-temperature polarized absorption and emission spectra and fluorescence lifetime were studied. The J-O theory was adopted to analyze the absorption spectra and results show that crystal exhibits relatively large intensity parameters Ω 2 and spectroscopic quality factor which is up to 3.12. At 453 nm, the absorption band is the strongest, and the corresponding cross-sections are 21.94 × 10 –20 cm 2 , 26.66 × 10 –20 cm 2 and 18.56 × 10 –20 cm 2 for the - X , - Y and - Z polarizations, respectively. The emission spectra also demonstrate the broad and strong emission band at 2030 nm. The FWHMs and cross-sections are 74 nm, 0.37 × 10 −20 cm 2 , 50 nm, 0.68 × 10 −20 cm 2 , and 49 nm 0.52 × 10 −20 cm 2 for the three polarizations, respectively. In addition, the crystal has a superior quantum efficiency which is as high as 97.1%. Taking all the analyses into account, it is reasonable to assert that the Ho 3+ :KBGM crystal an ideal candidate for ∼2 µm laser applications in many areas.
危险品化学品经营许可证（带存储）