Details

Autor(en) / Beteiligte

• Fisher, A.
• Park, Y.
• Lenz, M.
• Ody, A.
• Agustsson, R.
• Hodgetts, T.
• Murokh, A.
• Musumeci, P.

Titel

Single-pass high-efficiency terahertz free-electron laser

Ist Teil von

• Nature photonics, 2022-05, Vol.16 (6), p.441-447

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2022

Quelle

Springer Nature - Connect here FIRST to enable access

Beschreibungen/Notizen

• The terahertz gap is a region of the electromagnetic spectrum where high average and peak power radiation sources are scarce while at the same time scientific and industrial applications are growing in demand. Free-electron laser (FEL) coupling in a magnetic undulator is one of the best options for radiation generation in this frequency range, but slippage effects require the use of relatively long and low-current electron bunches to drive the terahertz FEL, limiting amplification gain and output peak power. Here we use a circular waveguide in a 0.96-m strongly tapered helical undulator to match the radiation and electron-beam velocities, allowing resonant energy extraction from an ultrashort 200-pC 5.5-MeV electron beam over an extended distance. Electron-beam spectrum measurements, supported by energy and spectral measurement of the terahertz FEL radiation, indicate an average energy efficiency of ~10%, with some particles losing >20% of their initial kinetic energy. A single-pass free-electron laser based on a waveguide in a tapered helical undulator is developed. The energy conversion efficiency from a relativistic electron beam to terahertz waves at 0.16 THz is ~10%.