Brilliant femtosecond-laser-driven hard X-ray flashes from carbon nanotube plasma

Brilliant X- and gamma-ray sources with ultrashort duration are widely pursued in fundamental science, industry and medicine. Compact femtosecond X-ray sources based on relativistic electrons accelerated by the laser wakefield in gases have performed outstandingly. Their energy conversion efficiency from laser to hard X-ray photons (> 10 keV) is, however, limited to 10(-7)-10(-5). Here we report the high-yield generation of hard X-ray flashes from targets made of carbon nanotubes, instead of gases. Orders-of-magnitude more electrons, accelerated to relativistic energy, are strongly wiggled inside a micrometre-scale, near-critical density plasma formed by the nanotube target, emitting 10(12) high-energy photons per shot. The yield of hard X-rays exceeds 10(10) photons per joule, corresponding to an unprecedented efficiency of 10(-3). Irradiated by upcoming 10-PW-class lasers, such targets can deliver 10-MeV photons with brightness outperforming existing sources by two orders of magnitude.

Automated summary

Brilliant X- and gamma-ray sources with ultrashort duration are widely pursued. Compact femtosecond X-ray sources based on relativistic electrons accelerated by the laser wakefield in gases have limitations in energy conversion efficiency. This study reports high-yield generation of hard X-ray flashes from carbon nanotube targets, resulting in an unprecedented efficiency. With upcoming 10-PW-class lasers, these targets can deliver 10-MeV photons with brightness outperforming existing sources by two orders of magnitude.