Researchers advance ultra-thin flat lens to capture perfect colors

Ultra-thin flat lenses suitable for photography are one step closer after a team of researchers at Harvard University made a major leap forward with its prototype wafer-thin flat lens. The new lens builds on the original prototype, which we first heard about in 2012, by using an achromatic metasurface to focus different wavelengths of light at the same point.

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> Ultra-thin flat lenses

Fresnel lenses are ultra-thin flat lenses. I’ve been trying to promote them but nobody in astronomy has been taking me seriously.

Does the continued reference to “achromatic” in the article mean that the lens isn’t “apochromatic” or does it just show off the ignorance of the writer? Apochromatic is better than achromatic.

mollwollfumble said:

> Ultra-thin flat lenses

Fresnel lenses are ultra-thin flat lenses. I’ve been trying to promote them but nobody in astronomy has been taking me seriously.

That’s because they are half asleep

they need to look at the new technology, and incorporate it into new equipment and telescopes

I’ve been trying to promote them but nobody in astronomy has been taking me seriously.

i wonder why?

CrazyNeutrino said:

mollwollfumble said:

> Ultra-thin flat lenses

Fresnel lenses are ultra-thin flat lenses. I’ve been trying to promote them but nobody in astronomy has been taking me seriously.

That’s because they are half asleep

they need to look at the new technology, and incorporate it into new equipment and telescopes

Nikon or Canon should design a astro astronomy telescope and use the new flat lens,

what if Nikon built a astro photography telescope using the new flat lens with the D810A built right in

some reason why the aren’t used in astronomy

http://modulatedlight.org/optical_comms/fresnel_lens_comparison.html

ChrispenEvan said:

some reason why the aren’t used in astronomy

http://modulatedlight.org/optical_comms/fresnel_lens_comparison.html

thats a old design, this is a newer design

and how do the new designs overcome diffraction limiting?

ChrispenEvan said:

and how do the new designs overcome diffraction limiting?

from the article

The development also means the new flat lens, dubbed an “achromatic metasurface,” does not suffer from the chromatic aberrations, or color fringing, that plague refractive lenses. As such, it will not require the additional bulky lens elements traditionally used to compensate for this chromatic dispersion in higher quality lenses.

this is the summary of the abstract
from
http://www.sciencemag.org/content/347/6228/1342.abstract

The replacement of bulk refractive optical elements with diffractive planar components enables the miniaturization of optical systems. However, diffractive optics suffers from large chromatic aberrations due to the dispersion of the phase accumulated by light during propagation. We show that this limitation can be overcome with an engineered wavelength-dependent phase shift imparted by a metasurface, and we demonstrate a design that deflects three wavelengths by the same angle. A planar lens without chromatic aberrations at three wavelengths is also presented. Our designs are based on low-loss dielectric resonators, which introduce a dense spectrum of optical modes to enable dispersive phase compensation. The suppression of chromatic aberrations in metasurface-based planar photonics will find applications in lightweight collimators for displays, as well as chromatically corrected imaging systems.

I dont have access to the full paper

Lighter telescopes would be great

CrazyNeutrino said:

Lighter telescopes would be great

If the gas runs out you can use the telescope to start your fire. Great camping survival idea that CN…….

:P

ChrispenEvan said:

and how do the new designs overcome diffraction limiting?

This one. They now use diffractive intra-ocular lenses for multifocals so people don’t need reading glasses after having their cataract surgeries done. But you need fairly non-observant type patients who can ignore the fizz in their vision. The surgeons I like most are the ones who don’t use them. Because I am the bunny having to explain later that no, I can’t make the vision sharper, it’s the payoff for being able to see at all distances at once.

But you need fairly non-observant type patients who can ignore the fizz in their vision.

and the reason they wont use them for telescopes. plus nearly all telescopes these days are reflectors.

buffy said:

It can’t make the vision sharper, it’s the payoff for being able to see at all distances at once.

Most people can resolve this problem by using specific magnification lenses for each focal distance required.

I carry three magnifications everywhere. I take other stuff back to the desk to apply other magnifications as required.