Q-Switched 2 µm fiber laser with molybdenum ditelluride saturable absorber

In this experiment, we demonstrate the application of a Molybdenum ditelluride (MoTe₂) thin film as a saturable absorber (SA) for inducing Q-switching in the 2.0 µm region. The fabrication of the MoTe₂ involved a bottom-up approach, where a three-electrode configuration was employed for electrodeposition onto a conductive film substrate. This method offers distinct advantages over conventional top-down approaches, as it proves to be more cost-effective and provides greater control over film thickness through precise manipulation of deposition time. The MoTe₂ thin film, nestled between two fiber ferrules, is seamlessly integrated into a Thulium-doped fiber laser (TDFL) cavity. Through this setup, we successfully realized a stable switched laser operating at 1910.3 nm, boasting a repetition rate of 4.61 kHz and a corresponding pulse width of 3.05 µs. Notably, the achieved pulse energy measured at 4.158 nJ, while the output power reached 0.173 mW under a maximum pump power of 677.04 mW at 1552 nm. These results indicate the promising potential of MoTe₂ thin films as efficient and reliable SAs for advancing Q-switched fiber laser technology in the mid-infrared spectral regime.