Anapole enhanced deep-ultraviolet third harmonic generation in a TiO2 metasurface

The deep ultraviolet (DUV) radiation source serves as a critical component in lithography systems, where its energy conversion performance significantly impacts applications in nanoscale photonics and quantum physics. This study presents a theoretical framework achieving exceptional third-harmonic generation with an efficiency higher than 10-2% in the DUV spectrum under optimal conditions and power scaling. Through carefully designed TiO2 nanostructures deposited on metal films, we observe pronounced anapole mode excitation that dramatically amplifies localized field intensities while facilitating nonlinear optical interactions. These findings provide crucial insights into how dielectric nanostructures with moderate refractive indices can manipulate DUV frequency conversion via anapole states, offering new possibilities for developing compact nonlinear optical devices and subwavelength light sources.