Multimillijoule terahertz radiation from laser interactions with microplasma-waveguides

Abstract

When a relativistic, femtosecond laser pulse enters a waveguide, the pulse energy is coupled into waveguide optical modes. The longitudinal laser field effectively accelerates electrons along the axis of the channel, while the asymmetric transverse electromagnetic fields tend to expel fast electrons radially outwards. At the exit of the waveguide, the $\sim$$\mathrm{nC}$, $\sim$$10\mathrm{MeV}$ electron bunch converts its energy to a $\sim$$10\mathrm{mJ}$ terahertz (THz) laser pulse through coherent diffraction radiation. In this paper, we present 3D particle-in-cell simulations and theoretical analyses of the aforementioned interaction process. We investigate the process of longitudinal acceleration and radial expulsion of fast electrons, as well as the dependence of the properties of the resulting THz radiation on laser and plasma parameters and the effects of the preplasma. The simulation results indicate that the conversion efficiency of energy can be over $5\%$ if the waveguide length is optimal and a high contrast pump laser is used. These results guide the design of more intense and powerful THz sources.

References in corpus (9)

• THz pulses over 50 millijoules generated from relativistic picosecond laser-plasma interactions
• Sequential terahertz pulse generation by photoionization and coherent transition radiation in underdense relativistic plasmas
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• Coherent Transition Radiation from Relativistic Beam-Foil Interaction in the Terahertz and Optical Range

Cited by in corpus (1)

• High-efficient harmonic vortex generation from a laser irradiated hollow-cone target