Random lasing and replica symmetry breaking in GeO2-PbO-MgO glass–ceramics doped with neodymium

• Published in: Scientific reports 2022-11, Vol.12 (1), p.19438-19438, Article 19438
• Main Authors: Câmara, Josivanir G., da Silva, Davinson M., Kassab, Luciana R. P., Silva-Neto, Manoel L., Palacios, Guillermo, de Araújo, Cid B.
• Format: Article
• Language: English
• Subjects: 639/301/1019; 639/301/1019/1020; 639/624; 639/624/1020; Ceramics; Crystallinity; Crystallization; Emissions; Humanities and Social Sciences; multidisciplinary; Neodymium; Photons; Science; Science (multidisciplinary); Symmetry; X-ray diffraction
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-23893-4

We investigated the random lasing process and Replica Symmetry Breaking (RSB) phenomenon in neodymium ions (Nd 3+ ) doped lead-germanate glass–ceramics (GCs) containing MgO. Glass samples were fabricated by conventional melt-quenching technique and the GCs were obtained by carefully devitrifying the parent glasses at 830 °C for different time intervals. The partial crystallization of the parent glasses was verified by X-ray diffraction. Photoluminescence (PL) enhancement of ≈ 500% relative to the parent glasses was observed for samples with a higher crystallinity degree (annealed during 5 h). Powders with grains having average size of 2 µm were prepared by griding the GCs samples. The Random Laser (RL) was excited at 808 nm, in resonance with the Nd 3+ transition 4 I 9/2  → { 4 F 5/2 , 2 H 9/2 }, and emitted at 1068 nm (transition 4 F 3/2  →  4 I 11/2 ). The RL performance was clearly enhanced for the sample with the highest crystallinity degree whose energy fluence excitation threshold (EFE th ) was 0.25 mJ/mm 2 . The enhanced performance is attributed to the residence-time growth of photons inside the sample and the higher quantum efficiency of Nd 3+ incorporated within the microcrystals, where radiative losses are reduced. Moreover, the phenomenon of Replica Symmetry Breaking (RSB), characteristic of a photonic-phase-transition, was detected by measuring the intensity fluctuations of the RL emission. The Parisi overlap parameter was determined for all samples, for excitation below and above the EFE th . This is the first time, for the best of the authors knowledge, that RL emission and RSB are reported for a glass–ceramic system.