SnSe2 realizes soliton rain and harmonic soliton molecules in erbium-doped fiber lasers.

Two-dimensional layered metal sulfides (TLMS) are widely used in battery anode materials, energy conversion, and semiconductor devices, because of their high energy storage characteristics, high thermoelectric characteristics, and large electron mobility. SnSe2 as a kind of TLMS has strong nonlinear optical characteristics. However, its research on dissipative system dynamics as a saturable absorber has not been studied. In this work, we obtained SnSe2 nanosheets using lithium ion intercalation. We reported a passively mode-locked fiber laser with SnSe2 as a saturable absorber to achieve the dissipative soliton generation. Due to the high third-order nonlinearity of SnSe2, the evolution of square wave pulses from 2 ns to 16 ns was obtained. After adjusting the polarization state, the evolution phenomenon of soliton rain with power and the soliton rain phenomenon with dual-wavelengths were obtained. Bound state harmonic phenomenon with a frequency of 313 MHz. Therefore, the strong nonlinear fiber laser based on SnSe2 provide a good platform for studying the pulsation, explosion, rainfall and other phenomena.