Matesurface has added another dimension to diffractive optics. In 2016, the Capasso team at Harvard University successfully developed a flat lens worked in visible spec-trum based on metasurface, which was named among Science Magazine's top discoveries of 2016. But the matelens could only focus one color at a time.The team reported an achromatic metalens (AML) operating over a continuous bandwidth in the visible in January 2017. The AML requires only a one-step lithog-raphy process with NA = 0.2 and a constant focal length over a continuous range of wavelengths 490 nm~550 nm.The building block of the AML consists of a titanium dioxide nanopillar with a square cross-section tiled on a silicon dioxide thin layer above a metallic mirror. With this approach, the researchers also designed a metalens with reverse chromatic dispersion, where the focal length increases as the wavelength increases.This method can effectively develop new components with desired dispersion in these applications such as im-aging under LED illumination, fluorescence.