Nickel–cobalt layered double hydroxide as a saturable absorber for continuous wave mode-locked laser

The nickel–cobalt (NiCo) layered double hydroxide (LDH) is prepared by ultrasonic liquid phase-assisted exfoliation method and dispersed onto mirror forming saturable absorber (SA). With NiCo-LDH SA, a continuous wave mode-locked laser at 1065.9 nm with a maximum output power of 1.72 W was achieved with a repetition frequency of 69 MHz and a pulse width of 18 ps. To the best of our knowledge, this is the first implementation of the NiCo-LDH as a SA for continuous wave mode-locked laser operation, which demonstrates the great potential of the NiCo-LDH for integration into lasers.