Integrated optical-field sampling with petahertz electronics*

Sub-cycle resolution sampling of arbitrary electric fields in time allows complete analysis of a system's electromagnetic response. This allows for many applications from tracking physical phenomena to biology and medicine. However, challenges arise when scaling to sampling visible and near-IR waveforms as these regimes ostensibly require high-energy optical sources and/or complicated apparatus. We circumvent these difficulties by using a chip-based approach that uses strong-field driven photoemission from plasmonic nanoantennas to generate attosecond electron bursts enabling a bandwidth greater than 1 PHz. Our integrated devices can sample arbitrary, low-energy waveforms, under ambient conditions, with attosecond time-resolution all on a chip. By tailoring the symmetry and arrangement of the patterned nanoantennas we can tune the responsivity of the devices for selective measurements. We have reconstructed the complete incident field illuminating our devices in amplitude, and phase, and demonstrated polarization sensitivity and selective sampling of specific polarizations. Additionally, we have shown how our time-resolved measurements of physical phenomena such as solid-state high harmonic generation can be used to tease apart the interplay of intra- and interband dynamics generating these high-order photons. Our work demonstrates a compact all-on-chip sampling technology with the requisite bandwidth and field sensitivity for myriad applications, enabling time-domain, optical-field-resolved spectroscopy of low-energy optical waveforms spanning visible to mid-infrared and even THz wavelengths.