Observation of photonic paramagnetic to spin-glass transition in a specially designed TiO 2 particle-based dye-colloidal random laser

• Published in: Optics letters Vol. 41; no. 15; p. 3459
• Main Authors: Pincheira, Pablo I R, Silva, Andréa F, Fewo, Serge I, Carreño, Sandra J M, Moura, André L, Raposo, Ernesto P, Gomes, Anderson S L, de Araújo, Cid B
• Format: Journal Article
• Language: English
• Published: United States 01.08.2016
• ISSN: 1539-4794
• DOI: 10.1364/OL.41.003459

Colloidal-based random lasers (RLs) are highly efficient and have been exploited in a wide range of geometries. However, in the particular case of ethanol solutions of rhodamines and TiO particles, the RL behavior is quite unstable due to the fast precipitation of the particles. In this Letter, specially designed amorphous TiO particles were synthesized by a sol-gel method, preventing the degradation of the RL for long operating lifetimes of over 10 shots. As a consequence, this modified colloidal RL allowed the observation of a clear replica-symmetry-breaking phase transition from the paramagnetic fluorescent to spin-glass RL behavior, which has not been observed in the system with nonfunctionalized TiO particles.