Electron Femtosecond Pulses

Field Emission Tip as a Nanometer Source of Free Electron Femtosecond Pulses.
Phys. Rev. Lett. 96, 077401 (2006)

Peter Hommelhoff, Yvan Sortais, Anoush Aghajani-Talesh, and Mark A. Kasevich

Physics Department, Stanford University, Stanford, California 94305, USA
(Received 25 July 2005; published 21 February 2006)

We report a source of free electron pulses based on a field emission tip irradiated by a low-power femtosecond laser. The electron pulses are shorter than 70 fs and originate from a tip with an emission area diameter down to 2 nm. Depending on the operating regime we observe either photofield emission or optical field emission with up to 200 electrons per pulse at a repetition rate of 1 GHz. This pulsed electron emitter, triggered by a femtosecond oscillator, could serve as an efficient source for time-resolved electron interferometry, for time-resolved nanometric imaging and for synchrotrons.

A spatially and temporally localized sub-laser-cycle electron source
Hommelhoff, Peter; Kealhofer, Catherine; Kasevich, Mark A. (2006-07-02) In Physical Review Letters 97 247402 (2006)

We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8 femtosecond low power laser pulses. This process is non-linear in the laser electric field, and the non-linearity can be tuned via the DC voltage applied to the tip.

Peter Hommelhoff and Catherine Kealhofer reviewing the "SPIDERgram" from Del Mar Photonics' Avoca SPIDER system.
New model Avoca 7 is suitable for sub-8 femtosecond pulses.

Sergey Egorov, President and CEO of Del Mar Photonics, checks field emission part in Peter Hommelhoff experimental setup.

Some of his earlier research in the Institute of Spectroscopy, USSR Academy of Sciences was related to laser-stimulated desorption, including laser-stimulated field desorption. See, for example:

Applied Physics B: Lasers and Optics, Springer Berlin, Heidelberg
Volume 45, Number 1, January, 1988

Abstract We report here on a experimental observation of photon-stimulated field emission of molecular anthracene ions from the surface of a layer adsorbed on a tungsten field-emitter tip. When the tip is irradiated with laser pulses 249, 308, and 400 nm in wavelength falling within the absorption bands of anthracene, the stimulated ion signal is proportional to the pulse fluence. The efficiency of the process decreases with the increasing laser wavelength. Photon stimulation is believed to be due to the resonance excitation of the anthracene molecules, followed by the field ionization of the excited molecules.