R N Maksimov

Laser ceramics with disordered crystalline structure

New ceramic materials based on yttrium oxide Y2O3 with isovalent (Yb2O3, Nd2 O3, and Lu2O3) and heterovalent (ZrO2 and HfO2) components are synthesized, and their spectroscopic properties are investigated. Possible channels of losses in the gain of stimulated radiation in the radiative transitions of Nd3+ and Yb3+ ions in ceramics with heterovalent additives are studied. The results of measurements of Y2O3 ceramics doped with zirconium and hafnium ions, the emission bandwidth and the lifetimes of the 4F3/2 and 2F5/2 levels of Nd3+ and Yb3+ ions, respectively, are presented. It is shown that the nonradiative population of the 4F3/2 levels of neodymium ions is due to their dipole-dipole interaction with Zr3+ and Hf3+ ions. Laser generation in [(Yb0.01Lu0.24Y0.75)2O3]0.88(ZrO2)0.12 ceramics with disordered crystalline structure was achieved at a wavelength of 1034 nm with a differential efficiency of 29%.

Investigation of lasing characteristics of domestic Yb : YAG laser ceramics

We report on the synthesis and laser characteristics of Yb3+-doped yttrium aluminium garnet (Y3Al5O12) optical ceramics. The ceramics was produced by solid-phase reactive sintering of a mixture of Yb (5 at %) : Y2O3 and Al2O3 nanopowders synthesised by laser ablation, using additional calcination of the mixture before compaction. In a thin disk geometry, multiwatt laser oscillation was obtained at a wavelength of 1030 nm with a power of 5.2 W and a slope efficiency of 37.0% at a pump pulse period-toduration ratio of 5.72.

Nd:YAG/Cr:YAG composite laser ceramics

This work reports the synthesis of transparent composite ceramics consisting of Nd:YAG in the central part and Cr4+:YAG in the edge cladding. The central part of ceramics was shaped like 14-mm-diameter disk or 11-mm-side square and an outer diameter of the edge cladding was 18 mm or 23 mm, respectively. The central part of ceramics had an optical transmittance of ~84% at a wavelength of 1.06 µm. The concentration of Cr4+ in Cr4+:YAG ceramics of three different compositions was estimated from the transmission spectra measured and known absorption cross sections. The optimal composition of edge cladding was estimated to be 2.5 mol % Cr + 0.5 mol % Ca + 97 mol % YAG to avoid self-excitation in Nd:YAG.