VSe2 nanosheets for ultrafast fiber lasers

Abstract

In this work, we investigate VSe₂ for generating femtosecond and large energy mode-locked laser pulses for the first time. Two types of VSe₂ based saturable absorbers (SAs), microfiber–VSe₂ and VSe₂/polyvinyl alcohol (PVA), are prepared, which exhibit strong nonlinear optical characteristics with a modulation depth (ΔT) of 22.5% and 1.849%, respectively. In contrast to other transition metal dichalcogenides (TMDCs), theoretical calculations show that VSe₂ is a metallic TMDC SA. With the implementation of microfiber–VSe₂, conventional soliton mode-locking Er-doped fiber (EDF) laser is demonstrated with an ultrashort pulse duration of 910 fs. Based on VSe₂/PVA, a large energy EDF laser is established. The maximum single pulse energy is 25.57 nJ. This study suggests that VSe₂ possesses application potential in ultrafast photonics and provides a valuable strategy for the development of TMDC based devices with desirable optoelectronic properties.