Single-shot terahertz-field-driven X-ray streak camera

A few-femtosecond X-ray streak camera has been realized using a pump–probe scheme that samples the transient response of matter to ionizing soft X-ray radiation in the presence of an intense synchronized terahertz field. Borrowing its concept from attosecond metrology, the femtosecond X-ray streak camera fills the gap between conventional streak cameras with typical resolutions of hundreds of femtoseconds and streaking techniques operating in the sub-femtosecond regime. Its single-shot capability permits the duration and time structure of individual X-ray pulses to be determined. For several classes of experiments in time-resolved spectroscopy, diffraction or imaging envisaged with novel accelerator- and laser-based short-pulse X-ray sources this knowledge is essential, but represents a major challenge to X-ray metrology. Here we report on the single-shot characterization of soft X-ray pulses from the free-electron laser facility FLASH. A streak camera for characterizing the ultrashort X-ray pulses produced by a free-electron laser is reported. The scheme has a single-shot capability, a resolution of a few femtoseconds and is expected to become a useful tool for X-ray metrology, including experiments involving time-resolved spectroscopy and imaging.