New split-ring resonator design paves way for high-resolution electron streak imaging
New split-ring resonator design paves way for high-resolution electron streak imaging lead image
Streak cameras are widely used in time-domain spectroscopy to measure how an electron pulse varies with time, but resolution of this method is constrained by the available electron deflection field. A new paper demonstrates the use of a new, sub-wavelength, rectangular split-ring resonator (SRR) in terahertz (THz)-frequency relativistic electron streak cameras, enhancing the camera’s deflection field amplitude by an order of magnitude and improving its time resolution.
SRRs concentrate radiation from a large area into a small gap, leading to an increase in the electromagnetic field. Shen et al. reported a field enhancement in the gap of their SRR by a factor of 10. When used in a streak camera, this field enhancement proportionally increases the temporal resolution for measuring a relativistic electron beam. These experimental results are in good agreement with simulations done by the group.
“This is the first time a sub-wavelength structure is utilized experimentally to enhance the field strength in a THz-driven relativistic electron streak camera,” said author Xinglai Shen.
Just one minor difference separates the group’s new SRR from a traditional design. Instead of a square loop, it consists of two rectangular rings sharing a side. The researchers optimized the dimensions of their resonator to tune into the THz frequency range while maintaining a physical size limitation. An additional benefit of this new design is the potential to stack multiple SRRs to further improve streak camera resolution.
According to the authors, this improvement in electron streak imaging has important applications in accelerator and beam physics, which require very small temporal resolution. “It paves the way to THz-driven relativistic electron streaking cameras with femtosecond and sub-femtosecond resolution,” said Shen.
Source: “A THz driven split-ring resonator based ultrafast relativistic electron streak camera,” by X. L. Shen, E. C. Snively, J. Giner Navarro, D. Cesar, and P. Musumeci, AIP Advances (2019). The article can be accessed at https://doi.org/10.1063/1.5080374 .
