On-chip multiwavelength achromatic thin flat lens

Abstract

Here we demonstrate a periodic array of thin flat lens defined on a silicon substrate on a standard silicon-on-insulator (SOI), which can focus light of broadband wavelength on the same focal plane. The on-chip thin flat lens has been implemented a periodic structure in the y-direction , but due to the high degree of dispersion of its structural units, the lens significantly suffers from large chromatic aberrations; And we also designed a fixed structure to keep the focal length of the thin flat lens unchanged at 1450 nm, 1550 nm, and 1650 nm, i.e. realizing the on-chip multiwavelength achromatic lens. In this way, functions previously unavailable for various on-chip imaging devices will be realized on this multi-band, which will help innovation in integration and imaging.