Carrier-envelope phase dependent photoemission from a nanometric metal tip

We tightly focus ~ 6fs Ti:sa pulses onto a nanome-tric metal tip and record photoelectron spectra at laser intensities of about ~ 4 × 10
¹¹
W/cm
²
. Here we present a strong carrier-envelope phase (CEP) dependent current modulation. In the high energy region of the spectra the CEP modulation rises up to 100%, meaning that the CEP can switch the photocurrent fully on and off. The metal tip resembles a record sensitive miniaturized CEP sensor with a precision exceeding about 15 mrad in 20s measurement time. Even CEP-stabilizing a Ti:sa-oscillator with the signal of the emitted photoelectrons of a tip seems feasible.