Dielectric Huygens’ metasurfaces with diverse functionalities in the range from near-UV to deep-UV

Abstract

Despite of great endeavors for extending the spectral range, there is still absent Huygens’ metasurfaces operating in the ultraviolet (UV). This work reports highly efficient dielectric Huygens’ metasurfaces in the spectral range from near-UV to deep-UV, which are made of dielectric materials with moderate refractive indices such as diamond and lithium tantalate. They can exhibit versatile functionalities in the UV range owing to their inherent physical nature. By employing their high transmittance and full 2π controllability of phase, we numerically demonstrate non-diffracting Bessel beam generation in the UV with a near-unity efficiency and compression of a chirped UV pulse with a duration of 88 fs down to 49 fs, as examples. In particular, we reveal that the dielectric Huygens’ metasurfaces can generate second harmonic radiations with high efficiency, for the first time to the best of our knowledge. Due to the spectral overlapping of the electric and magnetic resonances at the same wavelength, the dielectric Huygens’ metasurfaces generate highly enhanced local field in the nanodisks, enabling to obtain high nonlinear generation efficiency. The results show that vacuum UV radiation at 162 nm can be generated with efficiency in the order of 10−2% in transmission regime from the Huygens’ metasurface of LiTaO 3 nanodisk array. Diverse functionalities of dielectric Huygens’ metasurfaces in the UV region proposed in this work will find important applications for UV photonics.