Abstract-Terahertz-based subfemtosecond metrology of relativistic electron beams

R. K. Li, M. C. Hoffmann, E. A. Nanni, S. H. Glenzer, M. E. Kozina, A. M. Lindenberg, B. K. Ofori-Okai, A. H. Reid, X. Shen, S. P. Weathersby, J. Yang, M. Zajac, and X. J. Wang

https://journals.aps.org/prab/abstract/10.1103/PhysRevAccelBeams.22.012803

We demonstrate single-shot temporal characterization of relativistic electron bunches using single-cycle terahertz (THz) field streaking. A transverse deflecting structure consisting of a metal slit enables efficient coupling of the THz field and electron bunch. The intrinsically stable carrier envelope phase and strong gradient of the THz pulses allow simultaneous, self-calibrated determination of the time-of-arrival with subfemtosecond precision and bunch duration with single-femtosecond precision, respectively, opening up new opportunities for ultrafast electron diffraction as well as accelerator technologies in general.

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Abstract-Below gap optical absorption in GaAs driven by intense, single-cycle coherent transition radiation

J. Goodfellow, M. Fuchs, D. Daranciang, S. Ghimire, F. Chen, H. Loos, D. A. Reis, A. S. Fisher, and A. M. Lindenberg  »View Author Affiliations

Optics Express, Vol. 22, Issue 14, pp. 17423-17429 (2014)
http://dx.doi.org/10.1364/OE.22.017423

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-14-17423

Single-cycle terahertz fields generated by coherent transition radiation from a relativistic electron beam are used to study the high field optical response of single crystal GaAs. Large amplitude changes in the sub-band-gap optical absorption are induced and probed dynamically by measuring the absorption of a broad-band optical beam generated by transition radiation from the same electron bunch, providing an absolutely synchronized pump and probe geometry. This modification of the optical properties is consistent with strong-field-induced electroabsorption. These processes are pertinent to a wide range of nonlinear terahertz-driven light-matter interactions anticipated at accelerator-based sources.

© 2014 Optical Society of America