New tunable metasurface can act as axicon or metalens, with potential applications in biological imaging, microscopic measurement, laser fabrication, optical manipulation, multi-plane imaging, depth estimation, and optical data storage. The metasurface is made of titanium dioxide (TiO2) and can be actuated by rotating it between two layers. When light is incident on the metasurface, the rotation of the layers causes the phase of the light to be modulated, which can be used to create either a Bessel beam or a spherical wave front. Bessel beams are non-diffracting beams that can be used to image objects with high resolution. Spherical wave fronts can be used to focus light to different focal lengths. The tunable metasurface could be used to improve the performance of optical imaging systems in a variety of applications. The metasurface could also be used to fabricate optical components, such as lenses and mirrors. This could lead to the development of smaller, more efficient optical devices. Overall, the tunable metasurface is a promising new technology with the potential to revolutionize optical imaging and manipulation.
