Related Experiment Video
Updated: Mar 20, 2026

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
Published on: December 18, 2015
Demonstration of Coherent Terahertz Transition Radiation from Relativistic Laser-Solid Interactions
Guo-Qian Liao1, Yu-Tong Li1,2, Yi-Hang Zhang1
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Abstract:
Coherent transition radiation in the terahertz (THz) region with energies of sub-mJ/pulse has been demonstrated by relativistic laser-driven electron beams crossing the solid-vacuum boundary. Targets including mass-limited foils and layered metal-plastic targets are used to verify the radiation mechanism and characterize the radiation properties. Observations of THz emissions as a function of target parameters agree well with the formation-zone and diffraction model of transition radiation. Particle-in-cell simulations also well reproduce the observed characteristics of THz emissions. The present THz transition radiation enables not only a potential tabletop brilliant THz source, but also a novel noninvasive diagnostic for fast electron generation and transport in laser-plasma interactions.
Related Concept Videos
Interaction of EM Radiation with Matter: Spectroscopy
Electromagnetic Waves in Matter
Consider the electromagnetic wave passing through a dielectric medium. In such a case, Maxwell's equations get modified. In Ampere's law, ε0 , the dielectric permittivity of free space is replaced with ε, the permittivity of dielectric. Also, the vacuum permeability μ0 is replaced by the permeability of the medium, μ.
Furthermore,...
Atomic Nuclei: Larmor Precession Frequency
IR Absorption Frequency: Delocalization
In IR...
Atomic Absorption Spectroscopy: Radiation and Light Sources
Two common narrow-range 'line' sources used in AAS are hollow-cathode lamps (HCLs) and...
IR Absorption Frequency: Hybridization
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that...

