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DOE OSTI · 1656731

Transient work function gating: A new photoemission regime

Carbajo, S.
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Abstract

We present the theoretical basis for a new photoemission regime, transient work function gating (TWFG), which temporally and energetically gates photoemission and produces near-threshold photoelectrons with thermally limited emittance, percent-level quantum efficiency, and control over temporal coherence. The technique consists of actively gating the work function of a generalized photocathode using a non-ionizing long-wavelength optical field to produce an adiabatic modulation of the carrier density at their surface. We examine TWFG as a means to circumvent the long-standing trade-off between low emittance and high quantum efficiency, untethered to particle source or photocathode specifics. TWFG promises new opportunities in photoemission physics for next generation electron and accelerator-based x-ray photon sources.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICSFermi-Dirac statisticsSchottky barriersfree electron lasersoptical fieldparticle acceleratorsphotocathodesphotoexcitationsplasma accelerationquantum efficiencywork functions

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Carbajo, S.. 2020-07-10. Transient work function gating: A new photoemission regime. https://doi.org/10.1063/5.0011737

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