Abstract
Thermally-induced nucleation and growth of secondary crystalline phases in a parent glass matrix results in the formation of a glass ceramic. Localized, spatial control of the number density and size of the crystal phases formed can yield ‘effective’ properties defined approximately by the local volume fraction of each phase present. With spatial control of crystal phase formation, the resulting optical nanocomposite exhibits gradients in physical properties including gradient refractive index (GRIN) profiles. Micro-structural changes quantified via Raman spectroscopy and X-ray diffraction have been correlated to calculated and measured refractive index modification verifying formation of an effective refractive index, neff, with the formation of nanocrystal phases created through thermal heat treatment in a multi-component chalcogenide glass. These findings have been used to define experimental laser irradiation conditions required to induce the conversion from glass to glass ceramic, verified using simulations to model the thermal profiles needed to substantiate the gradient in nanocrystal formation. Pre-nucleated glass underwent spatially varying nanocrystal growth using bandgap laser heating, where the laser beam’s thermal profile yielded a gradient in both resulting crystal phase formation and refractive index. The changes in the nanocomposite’s micro-Raman signature have been quantified and correlated to crystal phases formed, the material’s index change and the resulting GRIN profile. A flat, three-dimensional (3D) GRIN nanocomposite focusing element created through use of this approach, is demonstrated.
© 2017 Optical Society of America
Full Article | PDF ArticleMore Like This
Myungkoo Kang, Laura Sisken, Justin Cook, Cesar Blanco, Martin C. Richardson, Ilya Mingareev, and Kathleen Richardson
Opt. Mater. Express 8(9) 2722-2733 (2018)
Enora Lavanant, Laurent Calvez, François Cheviré, Mathieu Rozé, Thomas Hingant, Raphaël Proux, Yann Guimond, and Xiang-Hua Zhang
Opt. Mater. Express 10(4) 860-867 (2020)
Brian Knorr, Keith Veenhuizen, Adam Stone, Himanshu Jain, and Volkmar Dierolf
Opt. Mater. Express 7(11) 4095-4110 (2017)