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Nanometer-sharp metallic tips are known to be excellent electron emitters. They are used in highest-resolution electron microscopes in cold field emission mode to generate the most coherent electron beam in continuous-wave operation. For…

Applied Physics · Physics 2018-11-16 Stefan Meier , Takuya Higuchi , Manuel Nutz , Alexander Högele , Peter Hommelhoff

We present femtosecond laser-induced electron emission from nanodiamond-coated tungsten tips. Based on the shortness of the femtosecond laser pulses, electrons can be photo-excited for wavelengths from the infrared (1932 nm) to the…

Applied Physics · Physics 2019-10-09 Alexander Tafel , Stefan Meier , Juergen Ristein , Peter Hommelhoff

This report demonstrates the most spatially-coherent electron source ever reported. A coherence angle of 14.3 +/- 0.5 degrees was measured, indicating a virtual source size of 1.7 +/-0.6 Angstrom using an extraction voltage of 89.5 V. The…

Mesoscale and Nanoscale Physics · Physics 2013-08-09 Josh Y. Mutus , Lucian Livadaru , Radovan Urban , Jason Pitters , A. Peter Legg , Robert A. Wolkow

In this article we present coherent control of above-threshold photoemission from a tungsten nanotip achieving nearly perfect modulation. Depending on the pulse delay between fundamental (1560 nm) and second harmonic (780 nm) pulses of a…

Irradiation of sharp silver tips with femtosecond laser pulses leads to photoassisted coherent field emission without a static field. We reconstruct the time profile of the emission, and show that the process is entirely governed by the…

We present an experiment studying the interaction of a strongly focused 25 fs laser pulse with a tungsten nanotip, investigating the different regimes of laser-induced electron emission. We study the dependence of the electron yield with…

A general challenge in various quantum experiments and applications is to develop suitable sources for coherent particles. In particular, recent progress in microscopy, interferometry, metrology, decoherence measurements and chip based…

Strong-field photoemission from nanostructures and the associated temporally modulated currents play a key role in the development of ultrafast vacuum optoelectronics. Optical light fields could push their operation bandwidth into the…

We demonstrate coherent control of photoemission from a gold needle tip using a two-color laser field. The relative phase between a fundamental field and its second harmonic imprints a strong modulation on the emitted photocurrent with up…

Optics · Physics 2021-08-11 Philip Dienstbier , Timo Paschen , Peter Hommelhoff

The emission times of laser-triggered electrons from a sharp tungsten tip are directly characterized under ultrafast, near-infrared laser excitation at Keldysh parameters $6.6< \gamma < 19.1$. Emission delays up to 10 fs are observed, which…

Ultrafast transmission electron microscopy (UTEM) has emerged as a versatile technique for the time-resolved imaging of nanoscale dynamics on timescales down to few-hundred attoseconds but the temporal and spatial resolutions are still…

Instrumentation and Detectors · Physics 2024-11-01 Alexander Schröder , Andreas Wendeln , Jonathan T. Weber , Masaki Mukai , Yuji Kohno , Sascha Schäfer

Photoelectron field emission, induced by femtosecond laser pulses focused on metallic nanotips, provides spatially coherent and temporally short electron pulses. The properties of the photoelectron yield give insight into both the material…

Applied Physics · Physics 2021-05-17 Eric R. Jones , Wayne Cheng-Wei Huang , Gobind Basnet , Bret N. Flanders , Herman Batelaan

We present energy-resolved measurements of electron emission from sharp metal tips driven with low energy pulses from a few-cycle laser oscillator. We observe above-threshold photoemission with a photon order of up to 9. At a laser…

Quantum Physics · Physics 2010-12-30 Markus Schenk , Michael Krüger , Peter Hommelhoff

Large area carbon nanotube (CNT) cathodes made from yarns, films or fibers have long been promising as next generation electron sources for high power radio frequency (rf) and microwave vacuum electronic devices. However, experimental…

Applied Physics · Physics 2023-01-18 Taha Y. Posos , Sergey V. Baryshev

It was already experimentally demonstrated that high-energy electrons can be generated using metal nanotips as active media. In addition, it has been theoretically proven that the high-energy tail of the photoemitted electrons is…

Optics · Physics 2015-06-18 M. F. Ciappina , J. A. Pérez-Hernández , T. Shaaran , M. Lewenstein

Field-emission patterns from a clean tungsten tip apex induced by femtosecond laser pulses have been investigated. Strongly asymmetric field-emission intensity distributions are observed depending on three parameters: (1) the polarization…

When two-color femtosecond laser pulses interact with matter, electrons can be emitted through various multiphoton excitation pathways. Quantum interference between these pathways gives rise to a strong oscillation of the photoemitted…

Optics · Physics 2022-05-24 Ang Li , Yiming Pan , Philip Dienstbier , Peter Hommelhoff

We demonstrate coherent control of multiphoton and above-threshold photoemission from a single solid-state nanoemitter driven by a fundamental and a weak second harmonic laser pulse. Depending on the relative phase of the two pulses,…

A coherent terahertz needle radiation emission mechanism is proposed. This mechanism can be realized in the experiments on femtosecond laser pulses interacting with surface of nanostructured ferromagnetic metal film. The proposed mechanism…

Optics · Physics 2008-09-30 Anatoly D. Gladun , Vladimir G. Leiman , Aleksey V. Arsenin

We report on sub-cycle terahertz light-field emission of electrons from tungsten nanotips under extreme conditions corresponding to a Keldysh parameter $\gamma_K\approx10^{-4}$. Local peak THz fields up to 40~GV/m are achieved at the apex…

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