Linear optical properties and Raman spectroscopy of natural fluorapatite

Abstract

Precision refractive indices and their dispersion in the visible and near IR range (430 -2400 nm) and thermal expansion (including its anisotropy and temperature dependence between 144 K and 673 K) were determined for gem-quality crystals of fluorapatite from Durango, Mexico. In addition, results of a polarized Raman spectroscopy study on these crystals are given. Fluorapatite crystals show moderate values of thermal expansion with small anisotropy. The linear optical properties of the crystals allow no phase matching for third harmonic generation, but signalize, together with the Raman characteristics, a potential suitability of fluorapatite as nonlinear optical material for χ (3) -based stimulated Raman scattering.

Stimulated Raman scattering in natural crystals of fluorapatite, Ca5(PO4)3F

“…In particular, several Raman studies on fluorapatite are given in literature . For the crystals used in the present work, polarized Raman data which agree well with data of an earlier investigation of synthetic fluorapatite are reported in . Figure shows a Raman spectrum taken in excitation geometry c ( a*a* ) c .…”

“…Chemical analyses of fluorapatite crystals from this locality can also be found in . The crystals employed for the present SRS study were investigated in detail with respect to their chemical composition, density and lattice parameters, thermal expansion as well as in terms of their temperature dependence, the optical transmission range, precision refractive indices and their dispersion from the visible to the mid‐IR range and spontaneous Raman spectroscopy in . The composition of crystals deviates only slightly from an ideal composition Ca 5 (PO 4 ) 3 F, with a minor substitution of F by Cl and a small content of rare earth ions La 3+ , Ce 3+ , and Nd 3+ (see Table ).…”

“…The volume of a single sector of the crystals is optically homogeneous with a uniaxial conoscopic image and of good optical quality that allows the present nonlinear lasing investigations. Selected data of the fluorapatite crystals are compiled in Table , details are given in .…”

“…The faces were polished but without anti‐reflection coating. The samples used for polarized spontaneous Raman scattering investigations given in were prepared from the same crystal as used for the preparation of the above sample I.…”

Lanthanum-Neodymium-Co-Substituted Calcium Fluorobritholites

“…All of these specifications allow these materials to be used in various fields such as chemical industry where the apatite ores are the main source of phosphate fertilizers and they are also used in phosphoric acid and various phosphate derivatives industry [9]. A further use of apatites is in optics [10] [11], in pharmaceuticals (excipient) and in chromatography (column) [12] [13] or as materials for laser [14].…”