Simulation of terahertz generation in corrugated plasma waveguides

Area of Science:

• Plasma physics
• Laser-plasma interactions
• Electromagnetic wave generation

Background:

• Corrugated plasma channels support unique electromagnetic modes with Floquet-type dispersion.
• Ultrashort laser pulses contain broad frequency bandwidths, including terahertz (THz) frequencies.
• Phase matching is crucial for efficient energy transfer from laser pulses to plasma modes.

Purpose of the Study:

• To simulate the response of a corrugated plasma channel to an ultrashort laser pulse.
• To demonstrate the production of terahertz (THz) frequency electromagnetic modes.
• To predict THz power output and mode structure for realistic plasma profiles.

Main Methods:

• Two-dimensional numerical simulations of laser-plasma interaction in corrugated channels.
• Analysis of electromagnetic mode dispersion and phase velocities.
• Calculation of THz power output and laser pulse depletion.

Main Results:

• Corrugated channels enable phase matching between laser ponderomotive potentials and channel electromagnetic modes.
• Significant excitation of THz radiation is possible due to the broad bandwidth of ultrashort pulses.
• Simulations predict approximately 1% laser energy conversion to THz in the linear regime, yielding 6 mJ for a 0.5 J pulse with <20 cm depletion length.

Conclusions:

• Corrugated plasma channels are effective for generating THz radiation from ultrashort laser pulses.
• The energy conversion efficiency is independent of laser energy in the linear regime.
• This method offers a promising route for compact THz sources.