Tuning optical properties of densified silica glass via high pressure and ultrafast laser excitation

Silica glass exhibits diverse structural configurations accompanied by densification under varying temperature and pressure conditions; these factors significantly influence its optical properties, such as the refractive index. However, the fundamental structural mechanisms underlying the optical properties change induced by high-pressure/high-temperature (HPHT) and femtosecond laser direct writing (FLDW) remain incompletely resolved. Herein, we report the similarities and differences in the optical responses of densified silica glass induced by these two methods. The most significant difference is that the laser-irradiated region evolves toward a glass structure characteristic of a high fictive temperature (1600−2000 K) by incorporating non-bridging oxygen defects associated with edge-sharing SiO4 tetrahedra, which induces distinctly different photoluminescence behaviors compared to high-pressure treatment. Our findings demonstrate the ability to locally tailor the glass structure to e..., , , # Data from: Tuning optical properties of densified silica glass via high pressure and ultrafast laser excitation: Open Source Data We have submitted our raw data included in our manuscript titled \"Tuning optical properties of densified silica glass via high pressure and ultrafast laser excitation\". ## Descriptions ### **fig1.csv** Figure 1 | Linear correlation between density change (Δρ) and refractive index change (Δn) in silica glass. The refractive index changes (Δn) are presented as a function of density change (Δρ) induced by femtosecond laser direct writing (FLDW) and high-pressure/high-temperature (HPHT) treatments. Data for FLDW were taken from Ponader et al. (36), Bressel et al. (42), Chan et al. (43), and Zhong et al. (44) and for HPHT from Guerette et al. (14) and Masuno et al. (45). The result from our HPHT experiment at 673 K is also plotted using a star symbol. The dotted line represents a linear fit obtained using reference data from various structural modification ...,