Few-layered ReS₂ as saturable absorber for 2.8  μm solid state laser

Area of Science:

• Materials Science
• Optics and Photonics
• Condensed Matter Physics

Background:

• Two-dimensional (2D) materials offer unique optical properties for laser applications.
• Transition metal dichalcogenides (TMDs) are a promising class of 2D materials.
• Rhenium disulfide (ReS2) is an emerging TMD with potential for optical modulation.

Purpose of the Study:

• To synthesize few-layered rhenium disulfide (ReS2) using a liquid phase method.
• To characterize the saturable absorption properties of ReS2 at 2.8 μm.
• To demonstrate the application of ReS2 as a saturable absorber in a passively Q-switched solid-state laser.

Main Methods:

• Liquid phase exfoliation for ReS2 synthesis.
• Open-aperture Z-scan technique for characterizing nonlinear optical properties.
• Fabrication and testing of a passively Q-switched solid-state laser incorporating ReS2.

Main Results:

• ReS2 exhibited saturable absorption with a saturation fluence of 22.6 μJ/cm² and a modulation depth of 9.7% at 2.8 μm.
• A passively Q-switched solid-state laser using ReS2 achieved a maximum output power of 104 mW at 920 mW absorbed pump power.
• The laser produced pulses with a pulse width of 324 ns and a repetition rate of 126 kHz.
• This work represents the first demonstration of ReS2 in an all-solid-state laser and the shortest pulses for 2D material-based Q-switched MIR lasers.

Conclusions:

• Few-layered ReS2 is a highly effective saturable absorber for mid-infrared (MIR) lasers.
• ReS2 demonstrates superior performance as an optical modulator for generating short-pulsed lasers.
• 2D ReS2 is a reliable and promising material for MIR solid-state laser applications.