Terahertz emission pattern from a single-color filament plasma

Area of Science:

• Plasma Physics
• Laser-Induced Plasmas
• Terahertz (THz) Emission

Background:

• Terahertz (THz) emission from laser-induced plasmas is a significant area of research.
• Understanding the angular distribution of THz emission is crucial for characterizing plasma properties and optimizing THz generation.

Purpose of the Study:

• To investigate the angular distribution of spectral components of THz emission from single-color laser filament plasma.
• To determine the relationship between the THz cone opening angle, plasma channel length, and THz frequency under different focusing conditions.
• To highlight the importance of specifying the collection angle for spectral analysis of THz radiation.

Main Methods:

• Experimental study of THz emission from single-color laser filament plasma.
• Measurement of the angular distribution of different spectral components of THz emission.
• Comparison of THz cone opening angle dependence under non-linear and linear focusing conditions.

Main Results:

• The opening angle of the THz cone is inversely proportional to the square root of plasma channel length and THz frequency in non-linear focusing mode.
• This dependence of the THz cone angle breaks down in the case of linear focusing.
• Experimental evidence shows that the spectral composition of THz radiation is dependent on the collection angle.

Conclusions:

• The angular distribution of THz emission from laser filament plasma is strongly dependent on focusing conditions and plasma parameters.
• Accurate characterization of THz radiation requires careful consideration of the experimental geometry, particularly the collection angle.
• These findings provide valuable insights for controlling and utilizing THz emission from laser-produced plasmas.