Uniform Tellurium Quantum Dots for Mode-Locked Fiber Lasers with Low Starting Threshold

Ultrafast lasers have extensive and important applications in precision processing, biomedicine, ultrafast spectroscopy research, and communication fields. Saturable absorber materials are key components in obtaining ultrafast lasers. However, at high mode-locked pump power, the saturable absorber is easily damaged, greatly reducing its operational stability and service life. Here, we report the synthesis of uniform tellurium quantum dots with an average size of ∼3 nm and stable traditional soliton mode-locked fiber laser achieved at an extremely low pump power of 30 mW, with an output pulse width of 700 fs based on the tellurium quantum dot saturable absorber. As the pump power further increased, the output pulse width was compressed to 578 fs at 150 mW. Even more interestingly, by adjusting the pump power, the phenomenon of bound soliton mode-locked was also discovered. The experimental results demonstrate that the synthesized uniform tellurium quantum dots exhibit an ultralow mode-locked threshold, enabling ultrafast laser operation at low pump powers. This material represents a promising saturable absorber with unique application potential.