TaSe2 nanosheets for harmonic mode-locked fiber laser

Passively harmonic mode locking of an erbium-doped fiber laser based on TaSe2 nanosheets saturable absorber (SA) is demonstrated. The TaSe2 nanosheets are prepared by the liquid phase exfoliation technology and then deposited onto side surface of a D-shaped fiber to form a fiber-compatible TaSe2 SA. The balanced twin-detector method is utilized to measure nonlinear absorption characterization of the fabricated SA, which gives saturable absorption, nonsaturable absorption, and saturation intensity as 5.49%, 24.6%, and 89.2 MW/cm2, respectively. Then, TaSe2 SA is inserted into a passively mode-locked erbium-doped fiber laser, and the fiber laser is demonstrated with a fundamental frequency of 7.1 MHz. By adjusting the polarization controller and pump power, harmonic mode-locking operation is realized. As the pump power increases to 380 mw, 128th harmonic mode-locked pulses at 908.8 MHz repetition rate are stably generated. The results confirm that TaSe2 is indeed a very desirable photonic material, which can be used in photonics, fiber optic communication, laser material processing and light modulators.