Ultra-broadband long-wave-infrared pulse production using a chirped-pulse difference-frequency generation

Area of Science:

• Optics and Photonics
• Nonlinear Optics
• Ultrafast Lasers

Background:

• Optical parametric chirped-pulse amplification (OPCPA) is a powerful technique for generating high-energy ultrafast laser pulses.
• Seeding OPCPA systems with broadband light sources is crucial for achieving broad spectral coverage in the output pulses.
• The long-wave-infrared (LWIR) region (8-12 µm) is of significant interest for various scientific and technological applications.

Purpose of the Study:

• To develop a novel broadband light source for seeding LWIR OPCPA systems.
• To achieve efficient generation and broadening of LWIR pulses.
• To enable the development of tabletop ultrafast terawatt-class LWIR OPCPA.

Main Methods:

• Utilized near-infrared chirped-pulse difference-frequency mixing.
• Employed a nitrocellulose pellicle in a Ti:sapphire regenerative amplifier to produce dual-frequency pulses.
• Mixed the pulses in a 0.4-mm AgGaS2 crystal.
• Applied genetic algorithm optimization to enhance spectral bandwidth.

Main Results:

• Generated LWIR pulses with a bandwidth of ~1 µm FWHM centered at 10.5 µm.
• Broadened the bandwidth to ~3 µm FWHM within the 8-12 µm atmospheric transmission window using genetic algorithm optimization.
• Demonstrated a seed source suitable for LWIR OPCPA.

Conclusions:

• The developed broadband light source is a key enabler for ultrafast terawatt-class LWIR OPCPA.
• This technology paves the way for compact and powerful laser systems in the LWIR spectral range.
• The method offers a pathway towards passively carrier-envelope-phase stabilized LWIR OPCPA systems.