Metasurface-based Ultrafast Optical Metrology

Ultrafast lasers have a wide range of applications, from enabling high-precision material processing and high-speed communication networks to advancing medical procedures and capturing ultrafast events. Metasurfaces are arrays of tiny optical structures that can manipulate light in remarkable ways, offering compact and lightweight optical components and enabling advancements in portable electronics. Despite that metasurfaces have been used for a wide range of optical elements and devices, there has been no attempt to utilize metasurfaces in ultrafast laser pulse characterization. This project aims to develop miniaturized metasurface-based ultrafast pulse characterization devices, enabling a broader adoption of ultrafast laser sources. The graduate and undergraduate students participating in this research will receive comprehensive training across various research disciplines. As part of this initiative, the Principal Investigator is committed to organizing open house events to showcase the research to pre-college students. The scientific findings of the proposed research will be broadly disseminated through regular scientific channels, community outreach, and media outlets. This project will develop compact metasurface-based devices capable of accurately characterizing both the temporal and spatial properties of the ultrafast optical pulses. These devices require a combination of linear and nonlinear metasurfaces. The ultrafast optical metrology requires nonlinear response of the components to demonstrate simultaneously high efficiency, wide bandwidth, and high directionality. This combination of requirements poses significant challenge for metasurface design. This project will provide a systematic solution to overcome these challenges and advance the field of ultrafast metrology. The project consists of three thrusts: 1) developing a nonlinear multipolar dielectric metasurface with high nonlinear efficiency, directionality, and broad bandwidth, 2) developing compact and accurate metasurface-based autocorrelator and frequency-resolved optical gating devices for temporal characterization of ultrafast optical pulses, and 3) developing a metasurface-based shearing interferometer for characterizing the spatial wavefront of ultrafast optical pulses. The designed devices are expected to have excellent signal-to-noise ratios. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.