Electro-optic sampling of near-infrared waveforms

Access to the complete electric field evolution of a laser pulse is essential for attosecond science in general(1), and for the scrutiny and control of electron phenomena in solid-state physics specifically(2-6). Time-resolved field measurements are routine in the terahertz spectral range, using electro-optic sampling (EOS)(7-9), photoconductive switches(10,11) and field-induced second harmonic generation(12,13). EOS in particular features outstanding sensitivity and ease of use, making it the basis of time-resolved spectroscopic measurements(14) for studying charge carrier dynamics(15-20) and active optical devices(21). In this Letter, we show that careful optical filtering allows the bandwidth of this technique to be extended to wavelengths as short as 1.2 mu m (230 THz) with half-cycle durations 2.3 times shorter than the sampling pulse. In a proof-of-principle application, we measure the influence of optical parametric amplification (OPA) on the electric field dynamics of a few-cycle near-infrared (NIR) pulse.