WxNb(1-x)Se2 nanosheets for ultrafast photonics

Ternary transition metal chalcogenides (TTMDCs), a novel type of two-dimensional (2D) three-element materials, possess multiple physical and chemical properties and have promising potentials in basic physics and devices. Herein, the usage of WxNb(1-x)Se2 nanosheets as a rising ultrafast photonic device to generate high power mode-locked and Q-switched pulses in a fiber laser is demonstrated. The WxNb(1-x)Se2 nanosheets were successfully prepared by the liquid exfoliation method with thickness less than 3 nm. The nonlinear optical absorption of the WxNb(1-x)Se2-based device was investigated with the saturable intensity of 40.93 MW cm(-2) and modulation depth of 5.43%. After integrating the WxNb(1-x)Se2-based device into an Er-doped fiber (EDF) laser cavity, mode-locking and Q-switching laser pulses were formed. In the mode-locked mechanism output, the pulse width is as narrow as 131 fs and the output power is 52.93 mW. In Q-switched operation, the shortest pulse duration is 1.47 mu s with the largest pulse energy of 257 nJ. Compared to recent studies, our results showed some improvements. This study suggests that 2D TTMDC-based devices could be developed as efficient ultrafast photonics candidates and widely used in nonlinear optical applications.

Automated summary

This study demonstrates the use of WxNb(1-x)Se2 nanosheets as ultrafast photonic devices to generate high power mode-locked and Q-switched pulses in a fiber laser. The results show improvements compared to recent studies, suggesting that 2D TTMDC-based devices could be efficient candidates for ultrafast photonics and nonlinear optical applications.