Efficient visible femtosecond optical parametric generator and amplifier using tilted pulse-front pumping.

Area of Science:

• Nonlinear optics
• Laser physics
• Materials science

Background:

• Group-velocity mismatch (GVM) limits efficiency in nonlinear optical processes like optical parametric generation.
• Femtosecond pulse generation requires precise control over pulse characteristics to maintain coherence and efficiency.
• Beta-barium borate (BBO) is a widely used nonlinear crystal for frequency conversion applications.

Purpose of the Study:

• To construct an efficient femtosecond optical parametric generator and amplifier (OPG/OPA) system.
• To compensate for group-velocity mismatch in three-wave interactions using tilted pulse fronts.
• To achieve tunable output in the visible and infrared regions with high energy and conversion efficiency.

Main Methods:

• Utilized pulses with tilted pulse fronts to mitigate group-velocity mismatch.
• Employed a collinear type-I phase-matched beta-barium borate (BBO) crystal.
• Operated the system with a 400-nm pump source at a 1-kHz repetition rate.

Main Results:

• Achieved tunable signal and idler outputs from 470 nm to 2.7 micrometers.
• Obtained femtosecond pulse widths in the range of 100–170 fs.
• Reached a maximum output energy of 6.5 microJoules.
• Demonstrated a total conversion efficiency exceeding 15%.

Conclusions:

• Tilted pulse front technique effectively compensates for GVM in femtosecond OPG/OPA systems.
• The developed BBO-based OPG/OPA is a highly efficient source for tunable femtosecond pulses.
• This system offers a valuable tool for various scientific applications requiring specific wavelengths and short pulse durations.