Terahertz-based subfemtosecond metrology of relativistic electron beams

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

doi:10.1103/physrevaccelbeams.22.012803

Abstract

Photons, electrons, and their interplay are at the heart of photonic devices and modern instruments for ultrafast science [1-10]. Nowadays, electron beams of the highest intensity and brightness are created by photoemission with short laser pulses, and then accelerated and manipulated using GHz radiofrequency electromagnetic fields. The electron beams are utilized to directly map photoinduced dynamics with ultrafast electron scattering techniques, or further engaged for coherent radiation production at up to hard X-ray wavelengths [11-13]. The push towards improved timing precision between the electron beams and pump optical pulses though, has been stalled at the few tens of femtosecond level, due to technical challenges with synchronizing the high power rf fields with optical sources. Here, we demonstrate attosecond electron metrology using laser-generated single-cycle THz radiation, which is intrinsically phase locked to the optical drive pulses, to manipulate multi-MeV relativistic electron beams. Control and single-shot characterization of bright electron beams at this unprecedented level open up many new opportunities for atomic visualization.

Highlights

Photons, electrons, and their interplay are at the heart of photonic devices and modern instruments for ultrafast science [1,2,3,4,5,6,7,8,9,10]
High power GHz rf sources and structures developed and perfected in past decades have been the workhorse for manipulating electron beams, ranging from compression of keV electron bunches for table-top ultrafast electron diffraction and imaging [14,15,16,17] to acceleration and temporal characterization of GeV electron beams in kilometer-long x-ray free electron lasers (XFELs)
Strong-field THz pulses have been used for XUV and x-ray pulse characterization with femtosecond resolution through photoelectron streaking [20,21,22], extracting eV-level-energy photoelectrons from nanotips and atoms through field emission [23], and THz acceleration [24,25,26] and manipulation [27,28,29] of in-vacuum free electrons with higher kinetic energies

Summary

Introduction

Electrons, and their interplay are at the heart of photonic devices and modern instruments for ultrafast science [1,2,3,4,5,6,7,8,9,10]. In a few recent demonstrations, subrelativistic, < 100 keV kinetic energy electron beams from DC sources were compressed using laser-generated THz fields to tens of femtoseconds, with their timing jitter stabilized to a few femtoseconds as characterized by THz streaking [30,31].

Results

Conclusion