Femtosecond laser-induced sub-wavelength plasma inside dielectrics: III. Terahertz radiation emission

Abstract

Electromagnetic radiation within the terahertz (THz) frequency range is of great interest for applications in remote sensing and time-domain spectroscopy. The laser-induced plasmas are promising mediums for generating THz radiation. It has been recently reported that focusing femtosecond Bessel pulses inside dielectrics induces a high aspect ratio over-critical plasmas. Here we show that the intense resonantly driven electrostatic fields at the so-called critical surface lead to THz radiation emission. Through three-dimensional particle-in-cell simulation and analytical derivation, we have investigated the emission of THz radiation. We show that the THz radiation is associated with a hot population of electrons trapped in ambipolar electric fields of the double layers.

10 pages, 4 figures, accepted for Physics of Plasmas

References in corpus (3)

• Generation of a Bessel beam in FDTD using a cylindrical antenna
• High energy density plasma mediated by collisionless resonance absorption inside dielectrics
• Femtosecond laser-induced sub-wavelength plasma inside dielectrics: II. Second-harmonic generation