Isotropic octupolar second harmonic generation response in LaBGeO5 glass-ceramic with spherulitic precipitation

Nhat Truong Lo (1) , Evelyne Fargin (1) , Marc Dussauze (2) , Luis Santos (3) , Hélène Vigouroux (1) , Alexandre Fargues (1) , Frédéric Adamietz (2) , Vincent Rodriguez (2)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 ISM - Institut des Sciences Moléculaires
3 CQE - Centro de Quimica Estrutural

A spherulitic crystallization of the crystalline phase LaBGeO5 is generated in the 25La2O3-25B2O3-50 GeO2 glass system. Linear and nonlinear optical properties of lanthanum borogermanate glass-ceramic have been investigated at both macroscopic and microscopic scales. Polarized μ-Raman analysis has evidenced a radial distribution of the crystallites along the c-axis inside spherulites, whereas polarized μ-Second Harmonic Generation (SHG) analysis revealed intensity maxima perpendicularly to the c-axis crystallites orientation. Polarized SHG mapping of a spherulite indicate that no dipolar response along the c-axis oriented crystallites occurs despite the individual dipolar symmetry C3 of the crystallites. At a larger mm scale, the isotropic scattering of spherulites recorded from macroscopic SHG experiment in the forward direction is consistent with an average coherent octupolar response per spherulite. These SHG analyses at different scale are both in accordance with radial antiferroelectric orientation along the c-axis of crystallites inside each spherulite.

Mots clés: Second harmonic generation; Polarization; Optical properties; Glass transitions; Raman spectra

Domaines: Matériaux

Nhat Truong Lo, Evelyne Fargin, Marc Dussauze, Luis Santos, Hélène Vigouroux, et al.. Isotropic octupolar second harmonic generation response in LaBGeO5 glass-ceramic with spherulitic precipitation. Applied Physics Letters, 2015, 106 (16), 161901 (4 p.). ⟨10.1063/1.4918808⟩. ⟨hal-01145534⟩