Probing of optical near-fields by electron Rescattering on the 1 nm scale.

We present a new method of measuring optical near-fields within ~1 nm of a metal surface based on rescattering of photoemitted electrons. With this method, we precisely measure the field enhancement factor for tungsten and gold nanotips as a function of tip radius. The agreement with Maxwell simulations is very good.

Attosecond control of electrons emitted from a nanoscale metal tip.

Attosecond science is based on steering electrons with the electric field of well controlled femtosecond laser pulses. It has led to the generation of extreme-ultraviolet pulses with a duration of less than 100 attoseconds (ref. 3; 1 as = 10(-18) s), to the measurement of intramolecular dynamics (by diffraction of an electron taken from the molecule under scrutiny) and to ultrafast electron holography.

Note: Production of sharp gold tips with high surface quality.

We present a simple method to produce sharp gold tips with excellent surface quality based on electrochemical etching with potassium chloride. Radii of curvature lie in the range of 20-40 nm and the surface roughness is measured to less than 0.8 nm.

Strong-field above-threshold photoemission from sharp metal tips.

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 intensity of ∼ 2 × 10(11)  W/cm2 the suppression of the lowest order peak occurs, indicating the onset of strong-field effects.