49 W carrier-envelope-phase-stable few-cycle 2.1 µm OPCPA at 10 kHz

Area of Science:

• Ultrafast laser science
• Mid-infrared optics
• Attosecond science

Background:

• Optical parametric chirped pulse amplification (OPCPA) is crucial for generating high-energy ultrashort pulses.
• Accessing the mid-infrared (MIR) spectrum with high power and stability is essential for advanced spectroscopic applications.

Purpose of the Study:

• To demonstrate a high-energy, femtosecond mid-infrared OPCPA system.
• To enable attosecond pump-probe spectroscopy experiments utilizing photon energies within the water window.

Main Methods:

• A kW-class Yb:YAG thin-disk amplifier was used to drive a self-seeded system.
• Short-wavelength-infrared (SWIR) generation was followed by three consecutive OPCPA stages.
• Carrier-envelope phase (CEP) stability was maintained throughout the process.

Main Results:

• The OPCPA system delivered 2.1 µm center wavelength pulses with 20 fs duration and 4.9 mJ energy at 10 kHz.
• The SWIR source achieved an average power of 49 W.
• Excellent phase and power stability were maintained, with sub-100 mrad CEP noise and 0.8% power fluctuations.

Conclusions:

• The developed MIR OPCPA system provides high-energy, ultrashort pulses with exceptional stability.
• This capability opens new avenues for attosecond pump-probe spectroscopy in the biologically relevant water window spectral region.