Transparent glass ceramics for 1300 nm amplifier applications

Abstract

The properties of an oxyfluoride glass ceramic that possesses high transparency after ceramming are described. Approximately 25 vol % of this material is comprised of cubic, fluoride nanocrystals and the remainder is a predominantly oxide glass. When doped with Pr+3, the fluorescence lifetime at 1300 nm is longer than in a fluorozirconate glass, suggesting that a significant fraction of the rare-earth dopant is preferentially partitioned into the fluoride crystal phase. This material has the added advantage of being compatible with ambient air processing.

Light scattering in transparent glass ceramics

“…In addition, the embedded crystalline phase can enhance existing, or offer entirely new, properties from that of the parent glass. Recently, much attention has been paid to optically transparent glass ceramics [2,3,4], which have greater thermal stability than their parent glasses. Transparent oxyflouride glass ceramics, for example, can be doped with optically active rare-earth cations, offering the possibility of numerous applications in nonlinear optics [3].…”

“…For example, Hopper [5] has developed an approximate structure factor for glasses which have undergone latestage microstructural phase separation via spinodal decomposition. Hopper's structure factor has been used to describe the scattering in transparent glass ceramics [3,4] and gives a turbidity ofwhere k is the wavevector of the incident light propagating in a medium with refractive indexn, ∆n is the difference in refractive index between the glass and crystal phases, and L is the mean distance between phases. This model improves on Mie theory, predicting turbidities that are somewhat closer to those measured for transparent glass ceramics.…”

“…For example, Hopper [5] has developed an approximate structure factor for glasses which have undergone latestage microstructural phase separation via spinodal decomposition. Hopper's structure factor has been used to describe the scattering in transparent glass ceramics [3,4] and gives a turbidity of…”

Crystallization behavior of new transparent glass-ceramics based on barium borate glasses

“…This is not the case for most transparent glass ceramics, or phase-separated glasses in which the scattering centers are spaced in the order of 10-50 nm, or 10 times smaller than the wavelength of visible light. Tick et al, 19) demonstrated that the angular dependence of scattering in these materials is not Rayleigh in nature. Only the BTF1 and BT1S3 samples showed better transparency than the corresponding glass samples.…”

Crystallization in Lead Tungsten Fluorophosphate Glasses

“…These rare earth doped materials exhibit highly efficient luminescent properties since rare earth ions tend to migrate to the heavy metal fluoride crystalline phase during heat-treatment. On the other hand, tungsten phosphate glasses based on the binary system NaPO 3 -WO 3 are well known for their great glass forming ability and very high thermal stability against devitrification due to the intermediary behavior of tungsten octahedra inside the metaphosphate network [8][9][10] . In addition, WO 3 incorporation decreases the overall phonon energy of the phosphate glass with formation of WO 6 clusters, resulting in interesting optical properties such as optical non linear absorption 11 , photochromic effects [12][13] and efficient luminescent properties when doped with rare-earth 14 .…”