Two-dimensional γ-graphyne for ultrafast nonlinear optical applications

In this work, γ-graphyne (γ-GY), a novel two-dimensional (2D) carbon allotrope, is demonstrated to have excellent ultrafast saturable absorption properties superior to that of graphene in the near infrared region. For practical application, the γ-GY nanosheets were directly dispersed in toluene in the existence of polymer, and were easily fabricated into flexible thin films. As proof-of-concept, the performances of γ-GY as a saturable absorber in passively Q-switched lasers and in all-optical switches were investigated. A minimum pulse width of 241 ns with the maximum pulse energy of 0.76 µJ and the corresponding peak power of 3.15 W was achieved for a γ-GY Q-switched solid-state laser at 1.06 µm. The γ-GY all-optical switching shows a rising/falling time of 1.46 ms/ 2.13 ms.