Robust nonlinear optical modulation based on niobium pentoxide in mid-infrared region

Here, we investigated the nonlinear optical properties of Nb₂O₅ nanoparticles in the mid-infrared region and their applications. Initially, the crystal structure and elemental distribution of Nb₂O₅ were characterized using FTIR and TEM/HRTEM. Subsequently, z-scan measurements revealed that Nb₂O₅ material exhibits strong saturable absorption properties at 2800 nm, with a modulation depth of 0.5. Furthermore, by employing Nb₂O₅ as a nonlinear modulator in a 2.8 μm erbium-doped ZBLAN fiber laser, the stable Q-switched laser pulse output was achieved, featuring a pulse width of 826 ns, a repetition rate of 93.5 kHz, and a signal-to-noise ratio of 40 dB. Additionally, the output efficiency of the system reached 18.2 %. Our results demonstrate that Nb₂O₅ is a robust nonlinear optical material with broad application potential in the field of optoelectronic applications.