Saturable Absorption of Copper Nanowires in Visible Regions for Short-Pulse Generation

A copper-nanowire (CuNWs)-based saturable absorber (SA) is utilized as a new Q-switcher for pulsed operations in visible regions. The plasmon resonance effect of CuNWs contributes to inducing the saturable absorption property. By incorporating the CuNWs-based SA into a red praseodymium $\Pr^{3+}$- doped ZBLAN fiber laser cavity, the red light shifts from a continuous wave (CW) state to a stable pulsed operation state. When it changes the injected pump power, the pulse repetition rate can be varied from 239.8 to 312.4 kHz. The narrowest pulse duration of this laser is 394 ns. Moreover, the maximum output power under a $Q$- switching operation is 9.6 mW. The results indicate that a CuNWs-based SA is an available Q-switcher for the red laser, revealing the potential of metal nanomaterials for short-pulse generation in visible regions.