Microscopy and Microanalysis

Special Section: Ultrafast Electron Microscopy

The Evolution of Ultrafast Electron Microscope Instrumentation

B.W. Reeda1 c1, M.R. Armstronga1, N.D. Browninga1a2, G.H. Campbella1, J.E. Evansa1, T. LaGrangea1 and D.J. Masiela1a2

a1 Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551, USA

a2 Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616, USA

Abstract

Extrapolating from a brief survey of the literature, we outline a vision for the future development of time-resolved electron probe instruments that could offer levels of performance and flexibility that push the limits of physical possibility. This includes a discussion of the electron beam parameters (brightness and emittance) that limit performance, the identification of a dimensionless invariant figure of merit for pulsed electron guns (the number of electrons per lateral coherence area, per pulse), and calculations of how this figure of merit determines the trade-off of spatial against temporal resolution for different imaging modes. Modern photonics' ability to control its fundamental particles at the quantum level, while enjoying extreme flexibility and a very large variety of operating modes, is held up as an example and a goal. We argue that this goal may be approached by combining ideas already in the literature, suggesting the need for large-scale collaborative development of next-generation time-resolved instruments.

(Received December 17 2008)

(Accepted March 23 2009)

Correspondence:

c1 Corresponding author. E-mail: reed12@llnl.gov