2025/01/21 by Alexandra Peña, C. Félix, Pena, Alexandra +5
Materials Science · #FOS: Physical sciences #Glass properties and applications #Optics (physics.optics)
paper · pdf · doi:10.48550/arxiv.2501.12496
openalex publication_date 2025/01/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This work aimed first at growing high quality bulk α-GeO2 crystals in their Quartz iso-structural form (α-SiO2), using a high temperature flux method. By optimizing the flux composition and the geometry and orientation of the seeds, it has been possible to achieve growth yields up to 90 % leading for the first time to bulk single crystals up to 3.5 cm3. Thanks to the optical quality and size of the obtained crystals, the second step of this study was the measurement of the optical activity of α-GeO2 between 0.3 and 2 μm. This gave access to the value of one of the independent components of the gyration tensor (g33) as a function of the wavelength. An α-SiO2 slab have been used to validate our methodology. Both crystals show a magnitude of optical activity of 3.4x10-5 rad/μm in the near IR range and great variations where the higher values are 3.4x10-3 rad/μm and 1.7x10-3 rad/μm at 0.3 μm for α-GeO2 and α-SiO2, respectively. The measurements are perfectly described by an empirical model that we propose and which relies on the macroscopic first-order electrical susceptibility and on the pitch of the structural helix compared to the wavelength of light.