Yb- and Er-doped fiber laser Q-switched with an optically uniform, broadband WS2 saturable absorber

TL;DR

This paper reports on the use of a solution-processed, broadband WS2 saturable absorber to achieve Q-switching in Yb- and Er-doped fiber lasers, demonstrating broadband sub-bandgap nonlinear optical absorption and ultrafast pulse generation.

Contribution

The study introduces a novel, solution-processed WS2 saturable absorber enabling broadband Q-switching in fiber lasers at 1030 and 1558 nm, highlighting its potential for ultrafast photonics.

Findings

Achieved self-starting Q-switched pulses with microsecond duration.

Demonstrated broadband sub-bandgap saturable absorption of WS2.

Operated at kilohertz repetition rates at two wavelengths.

Abstract

We demonstrate a ytterbium (Yb) and an erbium (Er)-doped fiber laser Q-switched by a solution processed, optically uniform, few-layer tungsten disulfide saturable absorber (WS2-SA). Nonlinear optical absorption of the WS2-SA in the sub-bandgap region, attributed to the edge-induced states, is characterized by 3.1% and 4.9% modulation depths with 1.38 and 3.83 MW/cm2 saturation intensities at 1030 and 1558 nm, respectively. By integrating the optically uniform WS2-SA in the Yb- and Er-doped laser cavities, we obtain self-starting Q-switched pulses with microsecond duration and kilohertz repetition rates at 1030 and 1558 nm. Our work demonstrates broadband sub-bandgap saturable absorption of a single, solution processed WS2-SA, providing new potential efficacy for WS2 in ultrafast photonic applications.