Tetragonal Ba₂MgGe₂O₇- a novel multifunctional optical crystal with numerous manifestations of nonlinear-laser effects: almost sesqui-octave Stokes and anti-Stokes combs and cascadedχ⁽³⁾↔χ⁽²⁾lasing with involved second and third harmonic generation

Optical properties of the germanate melilites Sr2MgGe2O7, Sr2ZnGe2O7 and Ba2ZnGe2O7

“…[16][17][18][19]), but in the following, with the exception of a study of electro-optic properties of several melilite crystals [20], no further interest in the melilites as optical materials is documented in the literature. In our recent study of nonlinear optical properties of the melilite crystal Ba 2 MgGe 2 O 7 the manifestation of numerous nonlinear optical effects based on χ (2) , χ (3) and cascaded χ (2) ↔ χ (3) processes was observed [1], that revived our interest in the melilite-group crystals. In the present work we report on the structure investigation of the germanate melilites Ba 2 ZnGe 2 O 7 , Sr 2 MgGe 2 O 7 and Sr 2 ZnGe 2 O 7 , their refractive indices and dispersion, and discuss their capability for phase-matching of collinear second harmonic generation (SHG).…”

“…Be, V) and the formation of various mixed crystals are known (for a more comprehensive overview see e.g. [1] were grown to large single crystals and in several cases were doped with lanthanides as laser crystals (see, e.g. [16][17][18][19]), but in the following, with the exception of a study of electro-optic properties of several melilite crystals [20], no further interest in the melilites as optical materials is documented in the literature.…”

Experimental and Theoretical Investigations on Structural and Vibrational Properties of Melilite-Type Sr2ZnGe2O7 at High Pressure and Delineation of a High-Pressure Monoclinic Phase

“…1 The general composition A 2 (T 1 ) 1 (T 2 ) 2 O 7 with melilite-type structure has A cations with eight-fold coordination and T 1 and T 2 cations with four-fold coordination. 1,2,9 The arrangements of tetrahedral units in melilite-type structures form nets of five membered rings. The same coordination for T 1 and T 2 cations favors the intermixing of the cations of these two sites and hence differences in local coordination around these sites have been observed in natural melilite-type and related structures.…”

“…Thus the studies on melilite-type silicates and germanates with different compositions have also drawn a significant attention for stimulated emission as well as for second and third harmonic generation. 1,2,9 Composition and temperature induced commensurate to incommensurate structural transitions, arising from the modulation of tetrahedral units, lead to rich crystal chemistry in melilite-type materials. [11][12][13][14] Thus, structural studies on such materials under non-ambient conditions, like temperature and pressure, have been performed in a number of related compounds.…”

Thermal and electromechanical properties of melilite-type piezoelectric single crystals

“…); the smaller site B is regular tetrahedral, which is occupied by divalent B 1 (Mg, Zn) and/or trivalent B 2 cation (Al, Ga); the smallest site C is a distorted tetrahedral, where trivalent C 1 cation (Al, Ga) and/or tetravalent C 2 cation (Si, Ge) occupy this position. 3,4 Melilite belongs to a tetragonal system with space group of 42 1 m, 5,6 the structure was firstly determined by Warren,7 and subsequently refined by Smith 8 and Bindi et al 9 Melilite crystals with a wide range of chemical compositions can be easily grown by Czochralski method, attracted attentions from scientists and engineers in the last decades. Much effort has been dedicated to the crystal growth and piezoelectric investigations.…”