Two-dimensional hexagonal boron nitride as saturable absorber for a 1.5 µm passively Q-switched erbium-doped fiber laser.

We report on two-dimensional (2D) hexagonal boron nitride (hBN) as saturable absorber (SA) material in a passively -switched erbium-doped fiber laser (EDFL) operating at 1.5 µm. The 2D hBN film as an SA is fabricated and transferred onto the optical fiber tip by natural deposition technology. In the -switched operation, we obtain stable -switched laser operation with a maximum average 10% output power of 2.25 mW, corresponding to a repetition frequency of 55.5 kHz, shortest pulse width of 6.77 µs, and single pulse energy of 40.49 nJ. The achieved PQS at 1.5 µm EDFL with 2D hBN as an SA may have potential applications in many novel 2D materials and all-fiber lasers.