Boosting terahertz generation in laser-field ionized gases using a sawtooth wave shape

Area of Science:

• Physics
• Optics
• Plasma Physics

Background:

• Broadband ultrashort terahertz (THz) pulses are crucial for various scientific applications.
• Current methods for THz generation in gases, such as plasma generation via femtosecond two-color laser pulses, have limitations in conversion efficiency.

Purpose of the Study:

• To enhance the efficiency of THz pulse generation in gases.
• To investigate the use of multiple-frequency laser pulses for optimizing THz waveform and electron dynamics.

Main Methods:

• Utilized multiple-frequency laser pulses to ionize noble gases.
• Employed a local current model for analytical study of THz generation.
• Performed comprehensive 3D simulations to account for propagation effects.

Main Results:

• Achieved a 2% conversion efficiency for THz generation, a significant improvement.
• Demonstrated that optimizing free electron trajectories with specific waveforms maximizes drift velocity.
• Validated analytical predictions through detailed 3D simulations.

Conclusions:

• Well-designed multicolor laser pulses can significantly improve THz conversion efficiency via tunnel ionization.
• The developed method offers a pathway to unprecedented performance in gas-based THz generation.