Mid-infrared mode-locked pulse generation with multilayer black phosphorus as saturable absorber.

Abstract

A mid-infrared saturable absorber mirror is successfully fabricated by transferring the mechanically exfoliated black phosphorus onto the gold-coated mirror. With the as-prepared black phosphorus saturable absorber mirror, a continuous-wave passively mode-locked Er:ZBLAN fiber laser is demonstrated at the wavelength of 2.8μm, which delivers a maximum average output power of 613mW, a repetition rate of 24MHz, and a pulse duration of 42ps. To the best of our knowledge, this is the first time a black phosphorus mode-locked laser at 2.8μm wavelength has been demonstrated. Our results demonstrate the feasibility of black phosphorus flake as a new two-dimensional material for application in mid-infrared ultrafast photonics.