Towards high power broad-band OPCPA at 3000 nm

Area of Science:

• Optics and Photonics
• Laser Physics
• Nonlinear Optics

Background:

• High-energy femtosecond laser pulses in the mid-infrared (MIR) are crucial for applications like strong-field physics and probing molecular vibrations.
• Existing MIR laser systems often face limitations in energy, pulse duration, or tunability.

Purpose of the Study:

• To develop and characterize a novel four-stage optical parametric chirped pulse amplifier (OPCPA) for generating high-energy, ultrashort MIR pulses.
• To achieve a central wavelength of 3000 nm with significant pulse energy and broad bandwidth.

Main Methods:

• Utilized a Ti:sapphire oscillator to seed both the OPCPA at 800 nm and the pump laser at 1030 nm.
• Employed a four-stage amplification process involving non-collinear and collinear optical parametric amplification and difference frequency generation in BBO, KTA, and LiIO3 crystals.
• Achieved pulse compression to 65 fs using sapphire and performed quantitative calculations to assess efficiency.

Main Results:

• Generated ultrashort pulses centered at 3000 nm with 430 μJ pulse energy and a 490 nm bandwidth.
• Demonstrated efficient amplification through a multi-stage OPCPA design.
• Confirmed near-optimal efficiency and low absorption losses, indicating suitability for high average power applications.

Conclusions:

• The developed four-stage OPCPA system successfully generates high-energy, ultrashort MIR pulses at 3000 nm.
• The system's design exhibits high efficiency and low losses, making it suitable for high average power and multi-kHz repetition rate operation.
• This advancement provides a valuable tool for research in strong-field physics, condensed matter, and molecular spectroscopy.