The demonstration of the slowing of single-cycle terahertz frequency (1012 Hz) electromagnetic pulses to subluminal speeds has been published in Nature Communications.
The work proves a new concept for velocity matching ultrashort, sub-picosecond, electromagnetic pulses with relativistic particle beams, opening up novels approaches for manipulating and accelerating femtosecond duration particle beams.
The ASTeC and the University of Manchester team involved, together with colleagues at Lancaster University, are now working to implement these concepts in experiments accelerating relativistic electron beams.
The Nature Communications article is open access and can be found at https://www.nature.com/articles/s41467-017-00490-y
Further information on our research in THz driven acceleration is available on the laser and optics group page.