4.3 μm CO₂-filled hollow-core fiber laser with a ring-cavity structure

Area of Science:

• Laser physics
• Optical engineering
• Materials science

Background:

• Gas-filled hollow-core fibers (HCFs) are emerging as a promising platform for mid-infrared (MIR) light generation.
• Previous research primarily focused on amplified spontaneous emission (ASE) sources, with limited exploration of cavity-based laser systems.

Purpose of the Study:

• To demonstrate, for the first time, a continuous-wave (CW) and self-Q-switched pulsed laser operating at 4.3 μm using a CO2-filled HCF.
• To investigate the potential of HCFs for generating pulsed MIR laser light.

Main Methods:

• A ring-cavity structure was employed with a carbon dioxide (CO2)-filled hollow-core fiber.
• Self-Q-switched pulsed laser operation was achieved by exploiting the ground-state self-absorption effect of CO2.

Main Results:

• A maximum CW laser output power of 1.09 W was achieved at 4.3 μm.
• For self-Q-switched operation, an average power of 244 mW, a pulse width of 142 ns, and a repetition rate of 2.8 MHz were obtained.
• This work represents the first demonstration of CW and self-Q-switched pulsed laser operation in a CO2-filled HCF.

Conclusions:

• The study successfully demonstrates a novel gas-filled HCF laser platform for generating MIR light.
• This research opens new avenues for developing Q-switched and mode-locked pulsed lasers in the MIR spectrum using HCFs.