Preparation of Bi₂Te₃ Based on Saturable Absorption System and Its Application in Fiber Lasers

Fiber laser is a fundamental component of laser systems and is of great significance for development of laser technology. Its pulse output can be divided into Q-switched and mode-locked. Achieving ultrashort pulse with narrower pulse duration and higher power is the focus of current research on mode-locked lasers. As an important component of fiber laser systems, saturable absorber (SA) can modulate losses in the optical cavity and generate pulses, enabling the laser system to achieve pulse output under long-term normal operating conditions better. Therefore, expanding the selection range of materials with better saturable absorption properties to improve the quality of pulse output is an important topic in current research. Here, the second generation topological insulator Bi₂Te₃ single crystal is prepared, and a ring fiber laser system is built with the Bi₂Te₃ SA. The mode-locked pulse with a pulse duration of 288 fs and a signal-to-noise ratio of 80.202 dB is realized. This result verifies that Bi₂Te₃, as a member of topological insulator, has good saturable absorption characteristics, and has broad prospects for the application research in lasers.