Spodumene, α-LiAlSi2O6 – A new natural SRS-active crystal with three χ(3)-promoting vibrational modes

• Published in: Optical materials 2018-04, Vol.78, p.235-246
• Main Authors: Kaminskii, Alexander A., Bohatý, Ladislav, Libowitzky, Eugen, Rhee, Hanjo, Lux, Oliver, Eichler, Hans J., Kleinschrodt, Reiner, Yoneda, Hitoki, Shirakawa, Akira, Becker, Petra
• Format: Article
• Language: English
• Subjects: Spodumene natural crystal; Stimulated Raman scattering
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2018.02.022

α-LiAlSi2O6, known as mineral spodumene, is introduced as a novel SRS-active crystal with monoclinic symmetry C2/c. Under picosecond laser excitation Raman-induced steady-state χ(3)-nonlinear generation in the visible and near-IR is observed in the crystals. All recorded Stokes and anti-Stokes high-order lasing components are identified and correspond to three SRS-promoting phonon modes with ωSRS1 ≈ 709 cm−1, ωSRS2 ≈ 357 cm−1 and ωSRS3 ≈ 1074 cm−1. On the basis of the results of a spontaneous Raman scattering study they were assigned to vibrations of the tetrahedral [SiO4] groups of the silicate chains and lattice modes of Li-O or Al-O of the crystal structure. A brief review in tabular form of so far known SRS-active natural crystals (minerals) is given as well. •Ino-silicate is new natural gem crystal for SRS and frequency comb generation.•Frequency comb generation from 0.537 to 1.37 μm.•50% transmission range from 0.37 to 2.7 μm.