Solid-state light-phase detector

Attosecond science relies on the use of intense, waveform-controlled, few-cycle laser pulses(1) to control extreme nonlinear optical processes taking place within a fraction of an optical period. A number of techniques are available for retrieving the amplitude envelope and chirp of such few-cycle laser pulses. However, their full characterization requires detection of the absolute offset between the rapidly oscillating carrier wave and the pulse envelope, the carrier-envelope phase (CEP). So far, this has only been feasible with photoelectron spectroscopy, relying on complex vacuum set-ups2-4. Here, we present a technique that enables the detection of the CEP of few-cycle laser pulses under ambient conditions. This is based on the CEP-dependence of directly measurable electric currents generated by the electric field of light in a metal-dielectric-metal nanojunction. The device holds promise for routine measurement and monitoring of the CEP in attosecond laboratories.