Abstract
We modify a scanning-force microscope tip/cantilever with a coaxial metal shield for use as an ultra-small field probe, observing 30 ps waveforms on an integrated circuit at a spatial resolution set by the tip radius, the first direct measurements of electric field at these levels of temporal and spatial resolution. This new ability to acquire topography while maintaining constant tip–sample distance for calibrated measurement or excitation of near-zone picosecond time-resolved electric fields is useful not only for probing advanced circuits but also for localized broadband spectroscopy of condensed matter and biological samples.