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Carbon Nanotubes as an Ultrafast Emitter with a Narrow Energy Spread at Optical Frequency
Author(s) -
Li Chi,
Zhou Xu,
Zhai Feng,
Li Zhenjun,
Yao Fengrui,
Qiao Ruixi,
Chen Ke,
Cole Matthew Thomas,
Yu Dapeng,
Sun Zhipei,
Liu Kaihui,
Dai Qing
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201701580
Subject(s) - femtosecond , materials science , ultrashort pulse , carbon nanotube , laser , field electron emission , electron , optoelectronics , temporal resolution , optics , nanotechnology , physics , quantum mechanics
Ultrafast electron pulses, combined with laser‐pump and electron‐probe technologies, allow ultrafast dynamics to be characterized in materials. However, the pursuit of simultaneous ultimate spatial and temporal resolution of microscopy and spectroscopy is largely subdued by the low monochromaticity of the electron pulses and their poor phase synchronization to the optical excitation pulses. Field‐driven photoemission from metal tips provides high light‐phase synchronization, but suffers large electron energy spreads (3–100 eV) as driven by a long wavelength laser (>800 nm). Here, ultrafast electron emission from carbon nanotubes (≈1 nm radius) excited by a 410 nm femtosecond laser is realized in the field‐driven regime. In addition, the emitted electrons have great monochromaticity with energy spread as low as 0.25 eV. This great performance benefits from the extraordinarily high field enhancement and great stability of carbon nanotubes, superior to metal tips. The new nanotube‐based ultrafast electron source opens exciting prospects for extending current characterization to sub‐femtosecond temporal resolution as well as sub‐nanometer spatial resolution.