Zeeman-effect-induced luminescence suppression in Er3+-doped GdF3 nanoparticles under dual-wavelength excitation

Magnetic field-modulated luminescence in lanthanide-doped nanomaterials offers crucial insights for advancing magneto-optical technologies, yet the fundamental mechanisms governing luminescence are still not fully understood. Here, we report Zeeman-effect-induced luminescence suppression in Er3+-doped GdF3 nanoparticles under dual-wavelength excitation (808 nm broadband and 527 nm narrowband) at moderate magnetic fields (up to 1.3 T). Under 808 nm excitation, upconversion emissions (528, 546, and 656 nm) dominated by two-photon absorption exhibit >79% intensity suppression (0.89 T), attributed to energy mismatch caused by Zeeman splitting of sublevels. In contrast, under 527 nm excitation, downconversion emissions (656, 842, and 983 nm) show uniform suppression (∼66% at 1.3 T) due to magnetic field-induced splitting of the 2H11/2 energy level. A simplified model elucidates how Zeeman splitting alters absorption resonance, with theoretical calculations aligning closely with experimental trends. This study reveals the physical mechanisms of magnetic field modulation using dual-wavelength excitation, providing a foundation for expanding magneto-optical technologies in imaging and sensing applications.