Fluoride optical nanoceramics

Abstract

The methods for preparation of highly transparent optical ceramics based on simple and complex fluoride compounds of elements of the first, second, and third Group in the Periodical system are considered. The use of precursors as nanopowders and processes of their self assembling on heating results in maximally homogeneous, transparent, and mechanically strong ceramics. The resulting calcium fluoride ceramics possess optical losses of 10 -2 -10 -3 cm -1 at 1.06 µm and shock resistance characterized by the fracture toughness К 1С = 4.7±0.3 MPa m 1/2 (for comparison, for a calcium fluoride single crystal К 1C = 1.5±0.15 MPa m 1/2 ). Regularities of the chemistry of fluoride nanopowders were considered in comparison with the oxide nanopowders: the fluorides are prone to hydrolysis, and powder nanoparticles precipitated from aqueous solutions have complex and heterogeneous (over the volume) chemical composi tion. The spectral luminescence properties of the ceramics activated by rare earth metals (Ce 3+ , Nd 3+ , Er 3+ , Yb 3+ ) or containing active color centers are presented. The generation properties of the lithium fluoride ceramics with the color centers and the ternary Ca-Sr-Yb fluoride during diode laser pumping are described.

The effects of the solution reactant concentration and temperature on the preparation of Pr3+:BaF2 transparent ceramics

“…However, the carbon and sulfur content have an increase with the increase of the reactant concentration of ceramic precursor powder, which can be mainly ascribed to the relatively high concentration of F − . 45 For this reason, there is an increasingly obvious hydrolysis effect with the increasing F − dissolved in the solvent. The hydrolysis effect of alkaline earth fluoride is a physicochemical change caused by the large contact area between the solvent and the small particle powder with a large specific surface area.…”

“…The results show that there is a relatively low nitrogen content for all samples. However, the carbon and sulfur content have an increase with the increase of the reactant concentration of ceramic precursor powder, which can be mainly ascribed to the relatively high concentration of F − 45 . For this reason, there is an increasingly obvious hydrolysis effect with the increasing F − dissolved in the solvent.…”

Fabrication and Sintering Behavior of Er:SrF2 Transparent Ceramics using Chemically Derived Powder

“…Since Ikesue et al reported the Nd:YAG transparent ceramic as a solid-state laser gain medium. Since Ikesue reported the Nd:YAG transparent ceramic as a solid laser gain medium [8], transparent ceramics doped with rare earth ions [9], such as YAG [10,11,12], sesquioxide [13,14,15,16,17] and fluoride [18,19,20,21,22,23], have been extensively investigated. Compared with single crystal, transparent ceramics can be fabricated on a large scale, can be mass produced, and can be homogenously and heavily doped with active ions [24,25,26].…”

Fluoride micropowders for laser ceramics

“…Laser fluoride ceramics is an independent line of investigation [3][4][5]. High quality CaF 2 optical ceramic samples with the optical absorption coeffi cient at a wavelength of 1 μm on the order of 10 -3 cm -1 resulted from using the hot pressing method [6][7][8][9][10].…”