Someone should tell Mr. Capasso that he could also use this technology to create the first "Star Wars like" Holograms ever. I think I know how that could be done with these flat lenses.
Fresnel lenses are almost flat too. Fresnel lenses are useful substitutes for magnifying glasses and useful for directing light in car lights or lighthouses. Fresnel lenses are uselessly bad for cameras because you can't get a clear image with them. Instead, you get a somewhat focused central point and radiating streaks of blur out from that which are bad enough to make most things unrecognizable. The reason is not optical quality or too few rings in the lens. The reason is common with these metasurfaces. Light passing through the middle isn't getting slowed in a flat lens like it is in a conventional single camera lens. As a result, a flat lens will have multiple parallel wavefronts collapsing simultaneously at the focal point. In other words, you don't have a single focal length with a flat lens. You have a range of focal lengths spanning from a minimum of the length along the perpendicular axis from the flat lens to the focal point to a maximum of distance from focal point to the outer edge of the flat lens. A conventional thick lens actually has only 1 focal length because the thicker central part of a thick lens slows light enough to match the extra time light takes to travel from its outer edge. There are comparatively much more minor issues of optical quality if your camera uses only one thick lens. These include problems such as chromatic aberration and spherical aberration but these are tackled to near perfection with extra correcting lenses. These aberrations are many orders of magnitude smaller than the focal length range problem with flat lenses, though. Even an inexpensive but magnifying glass often makes a recognizable image of the light source on a piece of paper. The same can't be said for a Fresnel lens. How does a metasurface lens get around this big problem of multiple focal lengths to produce conventional-camera-quality images?
Thanks! great talk.
Someone should tell Mr. Capasso that he could also use this technology to create the first "Star Wars like" Holograms ever. I think I know how that could be done with these flat lenses.
interesting
Fresnel lenses are almost flat too. Fresnel lenses are useful substitutes for magnifying glasses and useful for directing light in car lights or lighthouses. Fresnel lenses are uselessly bad for cameras because you can't get a clear image with them. Instead, you get a somewhat focused central point and radiating streaks of blur out from that which are bad enough to make most things unrecognizable. The reason is not optical quality or too few rings in the lens. The reason is common with these metasurfaces. Light passing through the middle isn't getting slowed in a flat lens like it is in a conventional single camera lens. As a result, a flat lens will have multiple parallel wavefronts collapsing simultaneously at the focal point. In other words, you don't have a single focal length with a flat lens. You have a range of focal lengths spanning from a minimum of the length along the perpendicular axis from the flat lens to the focal point to a maximum of distance from focal point to the outer edge of the flat lens. A conventional thick lens actually has only 1 focal length because the thicker central part of a thick lens slows light enough to match the extra time light takes to travel from its outer edge.
There are comparatively much more minor issues of optical quality if your camera uses only one thick lens. These include problems such as chromatic aberration and spherical aberration but these are tackled to near perfection with extra correcting lenses. These aberrations are many orders of magnitude smaller than the focal length range problem with flat lenses, though. Even an inexpensive but magnifying glass often makes a recognizable image of the light source on a piece of paper. The same can't be said for a Fresnel lens.
How does a metasurface lens get around this big problem of multiple focal lengths to produce conventional-camera-quality images?
👍 🔍
I did changed the playback speed to 1.25
daxx2k 1.75 is way more natural. This old geezer talks slower than a snail.