Ultrafast optical pulses exhibit a short time scale, high peak power, and wide spectral bandwidth, empowering numerous applications in multiple fields from spectroscopy and microscopy to manufacturing. Being able to control the properties of ultrafast pulses has been the backbone of ultrafast optics. In recent years, with advances in technology, we have witnessed great advances in engineering ultrafast pulses, not only temporally, but also spatially, generating complex space-time wave packets that were previously inaccessible. We review recent progress in spatiotemporally modulating ultrafast pulses. After discussing some of the more commonly used modulation approaches and devices and their latest developments, we focus on controlling both the spatial and temporal degrees of freedom of ultrafast pulses using metasurface optics. Various exotic pulses, including pulses carrying transverse orbital-angular momentum, diffraction-free light sheets, light-coils exhibiting spiral spatiotemporal intensity distribution, and dynamic beams that steer in space and time, are discussed. Finally, we provide a perspective on the challenges and opportunities for future development in synthesizing spatiotemporally structured light fields, especially by leveraging metasurface optics.
Chen et al. (Sat,) studied this question.