Low-loss Metasurface Optics down to the Deep Ultraviolet
Cheng Zhang, Shawn M. Divitt, Qingbin Fan, Wenqi Zhu, Amit K. Agrawal, Yanqing Lu, Ting Xu, Henri J. Lezec
Metasurfaces, planar arrays of subwavelength electromagnetic structures that collectively mimic the functionality of much thicker conventional optical elements, have been demonstrated at frequencies ranging from the microwave up to the visible. Here, we demonstrate low-loss metasurface optical elements operating at ultraviolet (UV) frequencies, including within the deep-UV range, and performing representative wave-front shaping functions, namely diffraction-limited lensing, beam bending, and hologram projection. The constituent nanostructures of the metasurfaces are formed of hafnium oxide - a lossless, high-refractive-index dielectric material deposited using low- temperature atomic layer deposition and patterned using high-aspect-ratio Damascene lithography. Our study opens the way to low form factor and multifunctional UV photonic platforms, that will benefit diverse applications in lithography, imaging, spectroscopy, and quantum information processing.