Defects and solarization in YAG transparent ceramics

A roadmap for laser optimization of Yb:Ca3(NbGa)5O12-CNGG-type single crystal garnets

“…Ultrashort laser pulses require optical gain media with a large fluorescence bandwidth. Most trivalent lanthanides (Ln 3+ ) do not fulfil this requirement due to the inner character of the 4f n orbital, but the situation is more favourable for Tm 3+ (4f 12 ) and Yb 3+ (4f 13 ). The near to full filling of the 4f orbitals for these latter ions favours electron interactions with lattice vibrations and their f-f spectroscopic bands are much broader than those observed for the rest of the Ln 3+ .…”

“…Solid state lasers have been demonstrated for years using either glass or single crystal doped hosts. Although the newer transparent ceramics technology [8][9][10] is gradually replacing the above hosts, there are still many applications which benefit from the use of single crystals, for instance in TW-PW short pulsed lasers the depolarization losses are minimized by crystal orientation 11,12 which cannot be achieved in ceramics, when UV Xe lamp pumping is required permanent solarisation of the presently developed YAG ceramics may appear, 13 or the larger Rayleigh light scattering of ceramics in the visible region may limit laser implementation in this spectral range. Furthermore, despite grain-oriented anisotropic fluorapatite ceramics being produced with limited optical transmittance for laser applications, 14,15 large cross section laser ceramics are basically restricted to optically isotropic media, i.e.…”

On fast LuAG:Ce scintillation ceramics with Ca2+ co‐dopants

“…It should be noted that, to preserve the charge balance of the host lattice, low‐valent Ca 2+ ion co‐doping will partially oxidize the Ce 3+ into Ce 4+ 29 . In addition, some point defects may be introduced to the lattice as well, such as oxygen vacancies or O − centers, 30 as described by the following defect equations 9 :…”

Broadening emission band of Yb:LuScO3 transparent ceramics for ultrashort pulse laser

“…The dark coloration caused by oxygen vacancies were removed through air annealing. 34 This result indicates the formation of the solid solution can increase the ceramic transmittance. As shown in Figure 6B, the Lu50 sample had an in-line transmittance higher than 76% in the 480-1200 nm range, with a maximum of 79% at 1100 nm, which is ~1.7 times as much as that of the Yb: (Lu x with Sc 2 O 3 , but also act as a sintering additive, 35 thereby affecting the densification behavior of ceramics during the sintering process, which led to differences in transmittance between samples.…”