Imaging from the visible to the longwave infrared wavelengths via an inverse-designed flat lens

It is generally assumed that correcting chromatic aberrations in imaging requires optical elements. Here, we show by allowing the phase image plane to be a free parameter, it possible correct variation of focal length over an extremely large bandwidth, from visible (Vis) longwave infrared (LWIR) wavelengths using single diffractive surface, i.e., flat lens. Specifically, designed, fabricated and characterized flat, multi-level lens (MDL) with thickness {\pounds} 10{\mu}m, diameter ~1mm, = 18mm, which was constant operating bandwidth l=0.45{\mu}m (blue) 15{\mu}m (LWIR). We experimentally point-spread functions, performance cameras comprised this MDL appropriate sensors. further simulations such extreme achromatic MDLs can achieved even at high numerical apertures (NA=0.81). By drastically increasing eliminating several refractive lenses, our approach enables thinner, lighter simpler systems.