Remote THz generation from two-color filamentation: long distance dependence.

Area of Science:

• Physics
• Optics
• Laser Science

Background:

• Terahertz (THz) wave generation is crucial for various applications.
• Two-color filamentation in gases is a promising method for remote THz generation.
• Understanding factors affecting remote THz signal strength is essential for practical implementation.

Purpose of the Study:

• To investigate the influence of filament onset position on remote terahertz (THz) generation.
• To quantify the decay of THz signals generated via two-color filamentation at distances up to 55 meters.
• To identify the primary physical mechanisms responsible for THz signal attenuation with increasing filament onset distance.

Main Methods:

• Experimental setup for remote THz generation using two-color filamentation.
• Measurement of THz signals emitted from filaments at varying distances (up to 55 m) from the laser source.
• Theoretical analysis to determine factors contributing to THz signal decay.

Main Results:

• THz signals were successfully measured from filaments generated at distances up to 55 meters.
• A monotonic decay in THz signal strength was observed as the filament onset position increased from 9 m to 55 m.
• Group velocity mismatch and linear diffraction were identified as the dominant factors causing the observed THz signal decay.

Conclusions:

• The onset position of two-color laser filaments significantly impacts remote THz generation efficiency.
• Group velocity mismatch and linear diffraction are critical limitations for long-distance remote THz generation.
• Optimizing filament formation and pulse propagation is necessary to enhance remote THz signal strength.