Speaker
Description
Optical sensors operating in extreme environments, such as aircraft engines, nuclear reactors and combustors, require materials capable of maintaining stable refractive-index modifications at elevated temperatures over extended periods. Femtosecond laser writing has emerged as a promising technique to induce such modifications inside glasses; however, preventing their thermal erasure remains a key challenge.
In this work, we investigate thermally stable refractive-index modifications written by near-infrared femtosecond laser irradiation in novel oxycarbide glass compositions. Glass beads fabricated by aerodynamic levitation were irradiated in bulk and characterised using quantitative birefringence measurements. Electron microscopy revealed nanopores and lamellar structures, confirming that the observed birefringence originates from laser-induced nanogratings. Thermal stability was assessed using 30-minute isochronal step-heating experiments.
In SiOC glass, the laser-written modifications remained detectable up to approximately 1270 °C. Although the birefringence disappeared around 1000 °C, a negative phase contrast persisted to higher temperatures. In addition, SiAlOC glass maintained a measurable birefringent response up to approximately 1250 °C. To the best of our knowledge, this is the first report of femtosecond-laser-induced birefringence in oxycarbide and aluminium-doped oxycarbide glasses, with erasure temperatures exceeding those of benchmark silica-based materials under comparable conditions
| I am the presenting author | Yes |
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