Bismuthene Nanosheets for 1 μm Multipulse Generation.

Area of Science:

• Materials Science
• Optics and Photonics
• Condensed Matter Physics

Background:

• Bismuthene is a novel two-dimensional material with notable electronic, mechanical, quantum, and nonlinear optical properties.
• Ultrafast photonics research increasingly utilizes bismuthene, yet its internal ultrashort pulse dynamics remain underexplored.

Purpose of the Study:

• To investigate the nonlinear optical properties of bismuthene nanosheets.
• To apply bismuthene as a saturable absorber (SA) in a passively mode-locked fiber laser.
• To explore the generation and evolution of ultrashort pulses within the laser system.

Main Methods:

• Characterization of bismuthene nanosheets' nonlinear optical properties.
• Fabrication of a fiber laser incorporating a bismuthene-based SA device.
• Analysis of laser output, including pulse characteristics and noise-like multipulse generation.

Main Results:

• Bismuthene nanosheets exhibited a saturation intensity of 2.4 MW/cm² and a modulation depth of 1%.
• A passively mode-locked fiber laser utilizing bismuthene SA generated unique noise-like multipulses.
• The narrow band gap of bismuthene and tapered fiber structure contributed to the observed pulsed laser dynamics.

Conclusions:

• Bismuthene is a promising material for ultrafast photonics applications, particularly as an SA in fiber lasers.
• The developed bismuthene-based fiber laser is suitable for applications in material processing and optical logics.
• Further exploration of bismuthene's ultrashort pulse dynamics is warranted.