Ceramic Lasers

Microstructure evolution of SiO2, ZrO2-doped Y3Al5O12:Nd3+ ceramics obtained by reactive sintering

“…liquid phase sintering seems not to be a predominant mechanism of YAG:Zr 4+ ceramics densification. Garnet doping by silica leads to liquid phase formation at 1400-1550 °ɋ, while YAG:Si 4+ solid solution occurs at higher temperatures [44]. Substitution of aluminum ions by silica imposes yttrium vacancies in the garnet structure.…”

Ce:YAG transparent ceramics based on nanopowders produced by laser ablation method: Fabrication, optical and scintillation properties

“…Growing high-quality large-sized single crystals with a homogeneous dopant distribution is difficult due to doping gradients in the melt. Ceramic technology offers the possibility for fabricating highly transparent and large-sized garnet materials at lower temperatures and with a homogeneous or controlled gradient activator ion distribution [3,4].…”

Multicenters in Ce3+ visible emission of YAG ceramics

“…The main defect in the melt-grown garnet crystals is an excess of large ions (Y 3+ , Gd 3+ , Lu 3+ ) that enter in the octahedral a-sites occupied normally by Al 3+ or Ga 3+ (antisites). When such a defect is close to the RE 3+ distortion of the local crystal field leading to the apparition of perturbed centers, which have been observed in the f-f transitions of the optical spectra as spectral P satellites accompanying the RE 3+ prevailing D 2 centers lines [9][10][11][12][13]. Significant differences in the relative intensities of the P satellites with respect to the main lines have been observed between the high temperature YAG grown single crystals, the flux grown crystals [8,9] or the transparent microceramics [12,13], leading to the conclusion that the Y 3þ Al antisites (Y 3+ in the a-octahedral Al 3+ sites) have smaller concentration in the last two cases.…”

“…When such a defect is close to the RE 3+ distortion of the local crystal field leading to the apparition of perturbed centers, which have been observed in the f-f transitions of the optical spectra as spectral P satellites accompanying the RE 3+ prevailing D 2 centers lines [9][10][11][12][13]. Significant differences in the relative intensities of the P satellites with respect to the main lines have been observed between the high temperature YAG grown single crystals, the flux grown crystals [8,9] or the transparent microceramics [12,13], leading to the conclusion that the Y 3þ Al antisites (Y 3+ in the a-octahedral Al 3+ sites) have smaller concentration in the last two cases. The concentration-dependent satellites could be determined by the crystal field perturbations inside the ensembles of RE 3+ ions in near sites, mainly pairs (M) [9][10][11][12][13].…”

“…Significant differences in the relative intensities of the P satellites with respect to the main lines have been observed between the high temperature YAG grown single crystals, the flux grown crystals [8,9] or the transparent microceramics [12,13], leading to the conclusion that the Y 3þ Al antisites (Y 3+ in the a-octahedral Al 3+ sites) have smaller concentration in the last two cases. The concentration-dependent satellites could be determined by the crystal field perturbations inside the ensembles of RE 3+ ions in near sites, mainly pairs (M) [9][10][11][12][13]. The satellites reported recently in IR spectra of Ce:YAG crystals (Czochralski grown) [1] and absent in crystalline thin films have been associated to perturbed Ce 3þ Y by nearby Y 3þ Al antisites and Ce 3þ Al , i.e.…”