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We propose a method to generate isolated relativistic terahertz (THz) pulses using a high-power laser irradiating a mirco-plasma-waveguide (MPW). When the laser pulse enters the MPW, high-charge electron bunches are produced and accelerated to ~ 100 MeV by the transverse magnetic modes. A substantial part of the electron energy is transferred to THz emission through coherent diffraction radiation as the electron bunches exit the MPW. We demonstrate this process with three-dimensional particle-in-cell simulations. The frequency of the radiation is determined by the incident laser duration, and the radiated energy is found to be strongly correlated to the charge of the electron bunches, which can be controlled by the laser intensity and micro-engineering of the MPW target. Our simulations indicate that 100-mJ level relativistic-intense THz pulses with tunable frequency can be generated at existing laser facilities, and the overall efficiency reaches 1%.
Owing to the rapid progress in laser technology, very high-contrast femtosecond laser pulses of relativistic intensities become available. These pulses allow for interaction with micro-structured solid-density plasma without destroying the structure
The microscopic dynamics of laser-driven coherent synchrotron emission transmitted through thin foils are investigated using particle-in-cell simulations. For normal incidence interactions, we identify the formation of two distinct electron nanobunch
We investigate the generation of broadband terahertz (THz) pulses with phase singularity from air plasmas created by fundamental and second harmonic laser pulses. We show that when the second harmonic beam carries a vortex charge, the THz beam acquir
Magnetic reconnection is a fundamental plasma process associated with conversion of the embedded magnetic field energy into kinetic and thermal plasma energy, via bulk acceleration and Ohmic dissipation. In many high-energy astrophysical events, magn
A new regime in the interaction of a two-colour ($omega$,$2omega$) laser with a nanometre-scale foil is identified, resulting in the emission of extremely intense, isolated attosecond pulses - even in the case of multi-cycle lasers. For foils irradia