Cu-MOF as a saturable absorber for mode-locking at 2 µm and beyond

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) offer tunable properties for optical applications.
• Saturable absorbers (SAs) are crucial for achieving mode-locking in lasers.
• Developing efficient SAs for fiber lasers is an active research area.

Purpose of the Study:

• To synthesize a copper-based metal-organic framework (Cu-MOF) for use as a saturable absorber.
• To fabricate and integrate the Cu-MOF SA into thulium-doped fiber lasers (TDFLs) and holmium-doped fiber lasers (HDFLs).
• To investigate the mode-locking performance and characteristics of the fiber lasers.

Main Methods:

• Synthesis of Cu-MOF using terephthalic acid and 1,2-bis(4-pyridyl)ethene.
• Fabrication of the SA by depositing Cu-MOF on an arc-shaped fiber.
• Incorporation of the SA into TDFL and HDFL setups.
• Characterization of laser output parameters including pulse width, energy, and power.

Main Results:

• Stable mode-locking operation was achieved in both TDFL and HDFL.
• The Cu-MOF SA demonstrated a modulation depth of 5.7% and saturation intensity of 13.8 MW/cm².
• TDFL achieved 6.82 mW average power, 1.08 ps pulse width, 464 pJ pulse energy, and 430 W peak power.
• HDFL achieved 2.64 mW average power, 1.75 ps pulse width, 180 pJ pulse energy, and 94.9 W peak power.

Conclusions:

• The synthesized Cu-MOF is an effective saturable absorber material for fiber lasers.
• The Cu-MOF-based SA enables stable and high-performance mode-locking in both TDFLs and HDFLs.
• This work highlights the potential of MOFs in developing advanced laser systems.