Altwaijry et al. demonstrate a simple all-solid-state device for the sampling of optical electric fields. The ability to directly measure the electric field of light enables novel observations of light-matter interactions, proving a powerful tool in modern ultrafast science including applications in petahertz electronics and molecular fingerprinting. In this work, Altwaijry et al. used an ultrashort light pulse in the visible-ultraviolet to induce an appreciable change in carrier density in a common semiconductor (gallium phosphide). The excitation lasts for a few femtoseconds and serves as a gate for linear photoconductive field sampling (LPS), where a measured current permits reconstruction of the electric field of a test pulse. We find that LPS relaxes the requirements on the gating pulse, intrinsically enabling broadband field sampling. In this work, LPS allowed for sampling the electric field of an NIR test pulse spanning one octave from 110 to 220 THz. The method overcomes some of the technical and physical limitations of commonly used field sampling techniques. As a simple all-solid-state device, it can be easily incorporated into any infrastructure, opening the door for sensitive field measurements and for well-defined probing of electron dynamics in solids.
