Watt-scale super-octave mid-infrared intrapulse difference frequency generation.

Area of Science:

• Optics and Photonics
• Laser Physics
• Mid-Infrared Technology

Background:

• High-power, broadband coherent mid-infrared (mid-IR) sources are crucial for applications in medical diagnostics, spectroscopy, and microscopy.
• Existing mid-IR sources often lack the required brightness, coherence, or compactness, necessitating large-scale synchrotron facilities.
• Emerging applications demand compact, high-brightness, coherent mid-IR radiation sources.

Purpose of the Study:

• To present a novel table-top, broadband, coherent mid-infrared light source.
• To achieve unprecedented brightness levels in the mid-IR spectral range.
• To enable advanced spectroscopy and microscopy techniques with a compact source.

Main Methods:

• Utilized a high-power, few-cycle Thulium (Tm)-doped fiber laser system operating at 1.9 µm.
• Employed intrapulse difference frequency generation (IPDFG) for mid-IR radiation generation.
• Ensured carrier-envelope-phase stability of the generated pulses.

Main Results:

• Demonstrated a table-top source of broadband, coherent mid-IR radiation (3.7–18 µm).
• Achieved brightness levels orders of magnitude higher than synchrotrons in the specified wavelength range.
• Generated carrier-envelope-phase stable pulses suitable for advanced applications.

Conclusions:

• The developed source offers a compact and highly bright alternative to synchrotron facilities for mid-IR applications.
• This breakthrough enables advanced spectroscopy and microscopy with unprecedented performance.
• The IPDFG method provides a robust pathway for generating phase-stable, high-power mid-IR pulses.