Tunable point defects in hydroxyl fused silica enabled by ultrashort laser pulses: photostimulated luminescence and functional module fabrication

Abstract

Three kinds of point defects, SiE’ center (≡ Si·), unrelaxed oxygen deficiency center (ODC (II)) and non-bridging oxygen hole center (≡ Si−O·, NBOHC), have been generated in hydroxyl fused silica by ultrashort pulsed laser irradiation. Hydroxyl is proved to be a decisive component for defect producing: NBOHC originates directly from hydroxyl; Hydroxyl facilitates the generation of SiE’ in an indirect way; No obvious relevance could be built between ODC (II) and hydroxyl. By improving hydroxyl content to 1000 ppm, NBOHC becomes the dominant defect species and its red luminescence is hence discernible to naked eye. Intended for application, high hydroxyl fused silica is screened out as the desired candidate, and NBOHC becomes the final interested defect. NBOHC’s intrinsic features of lifetime and temperature stability and extrinsic properties of laser condition dependence are specifically and systematically investigated. Prospective use of defect manipulation and fabrication in one-chip exploited for anti-counterfeiting and lab-on-a-chip is also discussed.