Functionalization of Optical Fibers with Rare-Earth Single Crystals for Application as Magneto-Optical and Magneto-Plasmonic Sensors

• Grant number: 25/05131-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2025
• End date: July 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Marcelo Nalin
• Grantee: Thiago Augusto Lodi
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

This project proposes the development of an innovative methodology for the large-scale synthesis of micrometric garnet single crystals using the controlled crystallization of oxide glasses. The method consists of melting a glass composition based on GeO¿-PbO-Bi¿O¿-X2O3-TR¿O¿ (X = Fe, Ga and Al; RE = rare-earth ions) at high temperatures (1200-1300 °C), followed by controlled cooling to induce phase separation and single-crystal crystallization. The crystal size can be adjusted by varying the cooling rate and temperature. The resulting glass-ceramic, composed of a vitreous matrix and a crystalline phase, undergoes an acid etching process to isolate the single crystals, which can be used individually or collectively as optical sensors. To expand their applicability, both conventional and unconventional optical fibers will be functionalized with these single crystals, enabling the development of advanced optical sensors for biomedical, chemical, and physical applications, with a particular focus on brain activity monitoring. Additionally, the multiplexing capacity of these sensors will be explored, allowing the simultaneous monitoring of multiple parameters in a single device, expanding its impact in several technological and scientific areas. Prototypes will be assembled and evaluated in laboratory conditions, followed by field tests to validate their robustness and applicability. This research has the potential to significantly contribute to the development of minimally invasive, highly sensitive sensors that are immune to electromagnetic interference.