Structural and optical characterization of ZrO2:CeO2 slab waveguides obtained via sol–gel

Planar multilayer ZrO2:CeO2 slab waveguides were prepared by a sol–gel route and dip-coating technique onto commercial glass substrates. The coatings were microstructurally characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and by optical confocal microscopy. Coating thicknesses of ca. 500 nm and refractive index values of 2.069 ± 0.001 and 2.087 ± 0.001, respectively for TE and TM light polarization modes, were calculated by Dark m-line spectroscopy. This is consistent with the birefringent character of the coating, associated to the presence of anisotropic crystalline phases within the coating’s vitreous matrix. Finally, propagation losses of 0.9 ± 0.2 and 1.5 ± 0.2 dB/cm were determined by the scattered light measurement for TE and TM polarization modes, respectively.

Planar multilayer ZrO2:CeO2 slab waveguides can be prepared easily by combining sol–gel and dip-coating methods on inexpensive commercial glass substrates. Tetragonal nanocrystals are found within the ca. 500 nm thick coatings, which cause the resulting waveguides to exhibit birefringence, an interesting property for the development of multifunctional devices.Figure optionsDownload high-quality image (228 K)Download as PowerPoint slideHighlights
► Preparation of slab waveguides on sodalime glass substrates via sol–gel dipcoating.
► TEM substrate/interface coating characterization.
► Structural and optical property analysis of waveguide coatings.
► Identification of birefringence arising from the presence of anisotropic nanocrystals.