High-coherence narrowband terahertz emission from a radially oscillating plasma oscillator

Area of Science:

• Plasma Physics
• Terahertz (THz) Science and Technology

Background:

• Generating narrowband terahertz (THz) radiation is crucial for advanced applications.
• Plasma-based THz sources often suffer from instability and broad spectral width.

Purpose of the Study:

• To present a novel method for generating narrowband THz emission.
• To investigate the use of a radially oscillating plasma oscillator in a plasma slab with a specific density profile.

Main Methods:

• Quasi-three-dimensional particle-in-cell simulations were employed to model plasma oscillations.
• A plasma slab with a longitudinal paraboliclike density profile was used to form the plasma oscillator.
• Comparison with a linear density gradient was performed to assess stability and coherence.

Main Results:

• Stable and longer-lived plasma oscillations were observed near the vertex of the parabolic density profile.
• Temporally coherent narrowband THz emission was achieved with a spectral width of approximately 0.66 THz.
• A spectral energy density efficiency of 0.01% per THz was measured, consistent with analytical predictions.

Conclusions:

• The parabolic density profile enhances plasma oscillation stability and coherence, leading to efficient narrowband THz generation.
• This method offers a promising approach for developing next-generation narrowband THz sources.
• Potential applications include THz-driven particle acceleration and ultrafast wireless communication.