Saturable optical absorption in MoS₂ nano-sheet optically deposited on the optical fiber facet

Molybdenum disulfide (MoS₂) nano-sheets have been successfully deposited directly on the cleaved facet of a silica optical fiber using optical trapping forces. By controlling the incident laser power, various types of MoS₂ films were deposited near the fiber core. An area selective deposition was successfully realized during the optical deposition process by using an optical reflectometry method. The presence of MoS₂ deposited layer at the fiber end was confirmed by microscopic Raman spectroscopy as well as scanning electron microscope images. Nonlinear response and power dependent transmission of the prepared sample was observed at the wavelength of 1552 nm, which can be used as an all-fiber saturable absorber. Moreover, the fabricated sample was inserted in a Er-doped fiber ring laser cavity and stable Q-switched pulses with the repletion rate from 26.6 kHz to 40.9 kHz were generated, which confirmed the potential of MoS₂ as a saturable absorber.