Abstract
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.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$209.00 per year
only $17.42 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
Data availability
The datasets for the beam energy spectrum as a function of charge and the interferometry scans at different beam energies are available from the corresponding author upon reasonable request.
Code availability
The GPT input file for simulating the entire Pegasus beamline, including the gun, the RF buncher linac and the interaction with the TE11 mode in the undulator, is available from the corresponding author upon reasonable request.
References
Dhillon, S. et al. The 2017 terahertz science and technology roadmap. J. Phys. D Appl. Phys. 50, 043001 (2017).
Lee, Y.-S. Principles of Terahertz Science and Technology Vol. 170 (Springer, 2009).
Salén, P. et al. Matter manipulation with extreme terahertz light: progress in the enabling THz technology. Phys. Rep. 836, 1–74 (2019).
Nanni, E. A. et al. Terahertz-driven linear electron acceleration. Nat. Commun. 6, 8486 (2015).
Thumm, M. High power gyro-devices for plasma heating and other applications. Int. J. Infrared Millim. Waves 26, 483–503 (2005).
Kemp, M. C. et al. in Terahertz for Military and Security Applications Vol. 5070 (eds Hwu, R. J. & Woolard, D. L.) 44–52 (SPIE, 2003).
Müller, A.-S. & Schwarz, M. in Synchrotron Light Sources and Free-Electron Lasers: Accelerator Physics, Instrumentation and Science Applications (eds Jaeschke, E. J., Khan, S., Schneider, J. R. & Hastings, J. B.) 83–117 (Springer, 2020).
Gallerano, G. P. et al. Overview of terahertz radiation sources. In Proc. 2004 FEL Conference (eds Bakker, R., Giannessi, L., Marsi, M. & Walker, R.) Vol. 1, 216–221 (JACoW, 2004).
Booske, J. H. et al. Vacuum electronic high power terahertz sources. IEEE Trans. Terahertz Sci. Technol. 1, 54–75 (2011).
Thumm, M. State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2017, KIT Scientific Report No. 7750 (KIT Scientific Publishing, 2018).
Kumar, N., Singh, U., Singh, T. & Sinha, A. A review on the applications of high power, high frequency microwave source: gyrotron. J. Fusion Energy 30, 257–276 (2011).
Elias, L. Free-electron laser research at the University of California, Santa Barbara. IEEE J. Quantum Electron. 23, 1470–1475 (1987).
Ramian, G. The new UCSB free-electron lasers. Nucl. Instrum. Methods Phys. Res. A 318, 225–229 (1992).
Oepts, D., Van der Meer, A. & Van Amersfoort, P. The free-electron-laser user facility Felix. Infrared Phys. Technol. 36, 297–308 (1995).
Gallerano, G., Doria, A., Giovenale, E. & Renieri, A. Compact free electron lasers: from Cerenkov to waveguide free electron lasers. Infrared Phys. Technol. 40, 161–174 (1999).
Jeong, Y. U. et al. First lasing of the KAERI compact far-infrared free-electron laser driven by a magnetron-based microtron. Nuclear Instrum. Methods Phys. Res. A 475, 47–50 (2001).
Knyazev, B., Kulipanov, G. & Vinokurov, N. Novosibirsk terahertz free electron laser: instrumentation development and experimental achievements. Meas. Sci. Technol. 21, 054017 (2010).
Gensch, M. et al. THz facility at Elbe: a versatile test facility for electron bunch diagnostics on quasi-CW electron beams. In Proc. 5th International Particle Accelerator Conference IPAC14 (JACoW, 2014); https://doi.org/10.18429/JACoW-IPAC2014-TUZA02
Shu, X. et al. First lasing of CAEP THz FEL facility. In Proc. 2017 42nd International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz) 1–2 (IEEE, 2017).
Li, H.-T., Jia, Q.-K., Zhang, S.-C., Wang, L. & Yang, Y.-L. Design of FELiChEM, the first infrared free-electron laser user facility in China. Chin. Phys. C 41, 018102 (2017).
Romaniuk, R. S. POLFEL-free electron laser in Poland. Phot. Lett. Poland 1, 103–105 (2009).
Nause, A. et al. 6-MeV novel hybrid (standing wave-traveling wave) photo-cathode electron gun for a THz superradiant FEL. Nucl. Instrum. Methods Phys. Res. A 1010, 165547 (2021).
Boonpornprasert, P. et al. Start-to-end simulations for IR/THz undulator radiation at PITZ. In Proc. FEL (eds Chrin, J., Reiche, S. & Schaa, V. R. W.) 153–158 (CERN, 2014).
Musumeci, P. et al. Advances in bright electron sources. Nucl. Instrum. Methods Phys. Res. A 907, 209–220 (2018).
Curry, E., Fabbri, S., Maxson, J., Musumeci, P. & Gover, A. Meter-scale terahertz-driven acceleration of a relativistic beam. Phys. Rev. Lett. 120, 094801 (2018).
Snively, E., Xiong, J., Musumeci, P. & Gover, A. Broadband THz amplification and superradiant spontaneous emission in a guided FEL. Opt. Express 27, 20221–20230 (2019).
Bartolini, R., Doria, A., Gallerano, G. & Renieri, A. Theoretical and experimental aspects of a waveguide FEL. Nucl. Instrum. Methods Phys. Res. A 304, 417–420 (1991).
Curry, E., Fabbri, S., Musumeci, P. & Gover, A. THz-driven zero-slippage IFEL scheme for phase space manipulation. New J. Phys. 18, 113045 (2016).
Savilov, A. V. Stimulated wave scattering in the Smith-Purcell FEL. IEEE Trans. Plasma Sci. 29, 820–823 (2001).
Gover, A. et al. Superradiant and stimulated-superradiant emission of bunched electron beams. Rev. Mod. Phys. 91, 035003 (2019).
Duris, J., Murokh, A. & Musumeci, P. Tapering enhanced stimulated superradiant amplification. New J. Phys. 17, 063036 (2015).
Sudar, N. et al. High efficiency energy extraction from a relativistic electron beam in a strongly tapered undulator. Phys. Rev. Lett. 117, 174801 (2016).
Maxson, J. et al. Direct measurement of sub-10-fs relativistic electron beams with ultralow emittance. Phys. Rev. Lett. 118, 154802 (2017).
Alesini, D. et al. New technology based on clamping for high gradient radio frequency photogun. Phys. Rev. Special Top. Accel. Beams 18, 092001 (2015).
Calvi, M., Camenzuli, C., Ganter, R., Sammut, N. & Schmidt, T. Magnetic assessment and modelling of the Aramis undulator beamline. J. Synchrotron Radiat. 25, 686–705 (2018).
Warren, R. Limitations on the use of the pulsed-wire field measuring technique. Nucl. Instrum. Methods Phys. Res. A 272, 257–263 (1988).
Zangwill, A. Modern Electrodynamics (Cambridge Univ. Press, 2013).
Fisher, A., Musumeci, P. & Van der Geer, S. Self-consistent numerical approach to track particles in free electron laser interaction with electromagnetic field modes. Phys. Rev. Accel. Beams 23, 110702 (2020).
Giannessi, L., Musumeci, P. & Quattromini, M. TREDI: fully 3D beam dynamics simulation of RF guns, bendings and FELs. Nucl. Instrum. Methods Phys. Res. At 436, 443–444 (1999).
Doria, A., Gallerano, G. P., Giovenale, E., Messina, G. & Spassovsky, I. Enhanced coherent emission of terahertz radiation by energy-phase correlation in a bunched electron beam. Phys. Rev. Lett. 93, 264801 (2004).
Sun, Y.-E. et al. Tunable subpicosecond electron-bunch-train generation using a transverse-to-longitudinal phase-space exchange technique. Phys. Rev. Lett. 105, 234801 (2010).
Musumeci, P., Li, R. & Marinelli, A. Nonlinear longitudinal space charge oscillations in relativistic electron beams. Phys. Rev. Lett. 106, 184801 (2011).
Muggli, P., Yakimenko, V., Babzien, M., Kallos, E. & Kusche, K. Generation of trains of electron microbunches with adjustable subpicosecond spacing. Phys. Rev. Lett. 101, 054801 (2008).
Boscolo, M., Ferrario, M., Boscolo, I., Castelli, F. & Cialdi, S. Generation of short THz bunch trains in a RF photoinjector. Nucl. Instrum. Methods Phys. Res. A 577, 409–416 (2007).
Zen, H., Ohgaki, H. & Hajima, R. Record high extraction efficiency of free electron laser oscillator. Appl. Phys. Express 13, 102007 (2020).
Orzechowski, T. et al. High-efficiency extraction of microwave radiation from a tapered-wiggler free-electron laser. Phys. Rev. Lett. 57, 2172–2175 (1986).
Acknowledgements
This work was supported by NSF grant no. PHY-1734215 and DOE grants nos. DE-SC0009914 and DE-SC0021190. The undulator construction was carried out under SBIR/STTR DE-SC0017102 and DE-SC0018559.
Author information
Authors and Affiliations
Contributions
A.F. and Y.P. carried out the measurements and analysed the data. M.L. and A.O. helped with UCLA Pegasus beamline operation, including alignment, vacuum and controls. P.M. proposed and supervised the experiment. A.M. participated in the TESSA development and is the principal investigator on one of the supporting grants. R.A. and T.H. were responsible for the undulator construction. A.F., Y.P. and P.M. prepared the manuscript, which was revised and edited by all co-authors.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Photonics thanks Lixin Yan and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Fisher, A., Park, Y., Lenz, M. et al. Single-pass high-efficiency terahertz free-electron laser. Nat. Photon. 16, 441–447 (2022). https://doi.org/10.1038/s41566-022-00995-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41566-022-00995-z
This article is cited by
-
Efficient free electron laser
Nature Photonics (2022)