Multipass-cell-based pulse compression to sub-two-cycle duration at 2 µm

Area of Science:

• Physics
• Optics
• Laser Science

Background:

• Ultrashort pulse generation is crucial for advanced scientific research.
• Shortwave infrared (SWIR) sources are valuable for nonlinear optics.
• Achieving sub-two-cycle pulses in the SWIR region with high power is challenging.

Purpose of the Study:

• To develop a high-power, ultrashort pulse laser source in the SWIR region.
• To demonstrate sub-two-cycle pulse compression using a multipass cell (MPC) in the SWIR.
• To establish a new benchmark for average power in SWIR ultrashort pulse lasers.

Main Methods:

• Utilized a thulium-doped fiber chirped-pulse amplification (Tm:fCPA) system.
• Employed a gas-filled multipass cell (MPC) for pulse compression.
• Operated at a repetition rate of 101 kHz to achieve high average power.

Main Results:

• Generated laser pulses with 11.0 fs duration at a 1.9 µm wavelength.
• Achieved a pulse energy of 1.36 mJ and average power of 137 W.
• Demonstrated the first MPC-based sub-two-cycle pulse compression in the SWIR region.

Conclusions:

• The developed SWIR laser source sets a new benchmark for average power.
• The source's high pulse energy and average power are ideal for nonlinear frequency conversion.
• This technology opens possibilities for generating radiation in terahertz, mid-infrared, and soft X-ray ranges.