Fiber-based source of 500  kW mid-infrared solitons.

Area of Science:

• Optics and Photonics
• Laser Physics
• Infrared Spectroscopy

Background:

• Fiber-based sources for ultrashort pulses are common in the near-infrared.
• Similar sources in the middle-wave infrared (mid-IR) are scarce but highly desired for spectroscopy and frequency metrology.
• Existing mid-IR sources often lack the high energy and repetition rates required for advanced applications.

Purpose of the Study:

• To design and demonstrate a fiber-based source capable of generating high-energy, few-cycle pulses in the mid-IR spectral domain.
• To achieve high peak power levels in the mid-IR using fiber laser technology.
• To enable new applications in molecular spectroscopy, frequency metrology, and coherent nonlinear processes.

Main Methods:

• Utilized multi-solitonic fission and soliton self-frequency shift in large mode area fibers.
• Employed picosecond pulses at 2 µm from a megahertz repetition rate fiber laser as the excitation source.
• Leveraged mature silica-based fiber technology up to 2.4 µm, with fluoride fiber used only in the final frequency-shifting stage.

Main Results:

• Successfully generated pulses with 50 nJ energy and 90 fs duration up to 2950 nm.
• Achieved a peak power of 500 kW.
• Demonstrated the potential for all-fiber format generation of ultra-broadband coherent continuum in the mid-IR.

Conclusions:

• The developed fiber source offers a promising solution for generating high-peak-power, ultrashort pulses in the mid-IR.
• This technology paves the way for significant advancements in high-resolution molecular spectroscopy and imaging.
• The use of mature fiber technologies makes this approach scalable and practical for various scientific and industrial applications.