Sub-three-cycle pulses at 2 µm from a degenerate optical parametric amplifier

Area of Science:

• Photonics and Laser Technology
• Nonlinear Optics
• Materials Science

Background:

• Ultrashort pulse generation is crucial for advanced spectroscopy and nonlinear optics.
• Accessing mid-infrared (MIR) wavelengths with femtosecond durations remains a challenge.
• Yb:KGW laser systems offer a robust platform for pumping optical parametric amplifiers.

Purpose of the Study:

• To develop a compact, two-stage optical parametric amplifier (OPA).
• To generate ultrashort pulses in the 1.7–2.5 µm range with few-microjoule energy.
• To leverage specific nonlinear crystals for broad phase-matching bandwidth.

Main Methods:

• Utilizing a two-stage optical parametric amplifier (OPA) architecture.
• Pumping the OPA at degeneracy with the fundamental output of a Yb:KGW laser.
• Employing bismuth triborate (BiBO) and periodically poled lithium tantalate (PPLT) crystals.

Main Results:

• Achieved ultrashort pulses with durations compressed to under 20 femtoseconds (fs).
• Output pulses spanned wavelengths from 1.7 to 2.5 µm (120–176 THz).
• Demonstrated few-microjoule pulse energies in the mid-infrared (MIR) spectral region.

Conclusions:

• The compact OPA system significantly broadens the availability of ultrashort MIR pulses.
• This advancement facilitates research in areas requiring high-energy, ultrashort MIR light.
• The use of BiBO and PPLT crystals at degeneracy is effective for achieving broad phase-matching bandwidth.