Optical anapoles excited by UV-A illumination

We report the excitation of optical anapole states at ultraviolet (UV) wavelengths. Numerical simulations indicate that TiO₂ nano-rectangles with varying length-to-width ratios can support such modes within the 350-380 nm range. We further propose a two-dimensional periodic arrangement of these nano-rectangles deposited atop a fused silica substrate. Understanding and manipulating optical anapole states in the ultraviolet spectrum is crucial for advancing next-generation photonic devices and enhancing nonlinear optical processes, such as generation of highly energetic vacuum ultraviolet light through third-harmonic generation.