Evaluation of carrier-envelope phase fluctuation in amplified pulse by using interference between harmonics generated on solid surface

This paper proposes an improved way of providing direct access to the CEP (φ) in low-energy pulses (nearly 1 μJ) by using the interference between the second harmonic (SH) and third harmonic (TH) from a solid surface. The interference signals are a superposition of a cos (2φ)-oscillation and a cos (3φ)-oscillation. The interference signals between the SH and TH from the surface do not include the constant phase shift caused by the linear dispersion. This makes it is possible to determine the CEP (φ) directly. In this experiment, the interference signals from the surface are found to exhibit CEP dependence for pulses comprising only a few optical cycles.