Phys.org July 22, 2022
Spaceplates are novel flat-optic devices that implement the optical response of a free-space volume over a smaller length, effectively “compressing space” for light propagation. Together with flat lenses such as metalenses or diffractive lenses, spaceplates have the potential to enable the miniaturization of any free-space optical system. The metrics of the ultimate limits of spaceplates bandwidth remains as a crucial roadblock for the adoption of this platform. An international team of researchers ( USA – Cornell University, University of Rochester, Canada) has derived the fundamental bounds on the bandwidth of spaceplates as a function of their numerical aperture and compression ratio. The general form of the bounds is universal and can be applied and specialized for different broad classes of space-compression devices, regardless of their implementation. Their findings also offer relevant insights into the physical mechanism at the origin of generic space-compression effects and may guide the design of higher performance spaceplates, opening new opportunities for ultra-compact, monolithic, planar optical systems for a variety of applications…read more. Open Access TECHNICAL ARTICLE
Comparison of a light beam converging at ′ in vacuum (or a background material) and at in the presence of an ideal spaceplate of length … Credit: Optica Vol. 9, Issue 7, pp. 738-745 (2022)