Curved lenses, like those in cameras or telescopes, are stacked in order to reduce distortions and resolve a clear image. That's why high-power microscopes are so big and telephoto lenses so long.
While lens technology has come a long way, it is still difficult to make a compact and thin lens (rub a finger over the back of a cellphone and you'll get a sense of how difficult). But what if you could replace those stacks with a single flat -- or planar -- lens?
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have demonstrated the first planar lens that works with high efficiency within the visible spectrum of light -- covering the whole range of colors from red to blue. The lens can resolve nanoscale features separated by distances smaller than the wavelength of light. It uses an ultrathin array of tiny waveguides, known as a metasurface, which bends light as it passes through, similar to a curved lens.
The article's description of the lens sounds reminiscent of a Fresnel lens. Perhaps Soylentils more familiar with the field can comment?
Related Stories
Xiaomi Teams Up with Light for Multi-Module Smartphone Cameras
Xiaomi and Light, a computational imaging firm, have announced at Mobile World Congress that the two companies will be working together to develop new multi-module cameras for smartphones. The two companies promised that the jointly-developed cameras will feature DSLR-level capabilities, but did not disclose when the first product from the joint project is expected to come to fruition.
Light specializes on computational imaging solutions using multiple camera arrays. The company has gone so far as to develop their own chip that can work with 6, 12, or 18-camera arrays. And while Xiaomi and Light aren't specifying just how big of a camera array they're looking to develop, we're likely looking at something in the lower-bounds of those number, if only due to the limited size of smartphones. For reference's sake, a 6-module camera would be very similar to what Nokia has done for their Nokia 9 PureView.
Cover the entire back of a smartphone with cameras, then gingerly hold it using the corners.
Related: Meta-Lens Works in the Visible Spectrum, Sees Smaller Than a Wavelength of Light
A Pocket Camera with Many Eyes - Inside the Development of Light
Caltech Replaces Lenses With Ultra-Thin Optical Phased Array
Nokia (HMD Global) Partners with Zeiss for Optics Capabilities
Google Reportedly Acquires Lytro, Which Made Refocusable Light Field Cameras
LG's V40 Smartphone Could Include Five Cameras
Leaked Image Shows Nokia-Branded Smartphone With Five Rear Cameras
(Score: 2) by kanweg on Sunday June 05 2016, @04:56AM
"Perhaps Soylentils more familiar with the field can comment?"
And can that person also say something about whether that the lens suffers from chromatic aberration quite a bit, as I suspect?
Bert
(Score: 3, Informative) by Scruffy Beard 2 on Sunday June 05 2016, @05:08AM
Looks like this new lens avoids chromatic aberration by having nano-scale features.
From Wikipedia:
From TFA:
Psuedo-edit: not sure how they solve the diffraction problem.
(Score: 3, Informative) by inertnet on Sunday June 05 2016, @09:30AM
Simulation video here: http://www.bbc.com/news/science-environment-36438686 [bbc.com]
(Score: 2) by wonkey_monkey on Sunday June 05 2016, @09:48AM
Music to go with simulation video here: https://www.youtube.com/watch?v=75V4ClJZME4 [youtube.com]
systemd is Roko's Basilisk
(Score: 3, Funny) by inertnet on Sunday June 05 2016, @10:27AM
I would have picked this music: https://www.youtube.com/watch?v=sKc7GQfxTY4 [youtube.com]
(Score: 0) by Anonymous Coward on Sunday June 05 2016, @12:06PM
What am I supposed to sense by rubbing a finger over the back of a cellphone?
(Score: 4, Interesting) by rleigh on Sunday June 05 2016, @12:29PM
I assume a bump as seen on current thin phones, which is required to accommodate the bulk of the optics (already miniaturised and making significant compromises in image quality).
If this does work as promised and is easy to scale up for bulk manufacture, it would be a revolution in optical engineering. Both for phones and other small devices--the "lens" could be laminated to the surface material and be small and unobtrusive, as well as cheaper. And also for serious optics like in microscopes, telescopes etc. In a good quality microscope, single lenses can cost several tens of thousands (and more); big telescope lenses are even more bulky and expensive. If you can replace these with something of comparable quality but which can be manufactured as a thin film, you could make billions.
As someone else mentioned, chromatic and other aberrations might be something which needs more investigation. Glass lenses already make compromises to accommodate different wavelengths--they are only optimal at a single wavelength. Does this technology eliminate or reduce the problem, or is it worse?
Either way, it certainly promises to be exciting for some applications, even if those applications are initially limited.
(Score: 0) by Anonymous Coward on Sunday June 05 2016, @01:05PM
My guess -- the first big applications will be for spy satellites. The telescope mirrors they use now are fabricated from glass (or other materials) with internal cutouts to save launch weight.
(Score: 4, Informative) by cellocgw on Sunday June 05 2016, @03:38PM
Take a look at any info page: a Fresnell lens is essentially a regular convex lens with the "fat parts" cut out. You end up with a thin lens made up of concentric "circles" each of which has the curvature (tilt) that a full convex lens would have at that radius, but without the lens' thickness.
The lens in this article is completely different: metamaterials are fabricated on a nano-scale, and work by way of interferometric interactions between the light's wavefront (phase front) and the structure of the nanomaterial. A classic lens, including Fresnell, works due to the difference in index of refraction between air and glass, and Snell's law thereof.
(and yes, I am an optical physicist)
Physicist, cellist, former OTTer (1190) resume: https://app.box.com/witthoftresume
(Score: 2) by Fnord666 on Sunday June 05 2016, @06:43PM
The lens in this article is completely different: metamaterials are fabricated on a nano-scale, and work by way of interferometric interactions between the light's wavefront (phase front) and the structure of the nanomaterial. A classic lens, including Fresnell, works due to the difference in index of refraction between air and glass, and Snell's law thereof.
(and yes, I am an optical physicist)
Question for you. Some of the discussion of this lens seemed to indicate that the lens only worked for one wavelength of light. To work on a different wavelength the nanostructures would have to be reorganized. Is that correct?
(Score: 2) by cellocgw on Sunday June 05 2016, @07:56PM
Yes, that's my impression as well (that the current design is monochromatic). From what little I know of current metamaterial designs, the physical spacing of the layout only fits one wavelength. There's always some "bandwidth" the same way an FM receiver can handle a signal thats slightly off-center frequency, but that's about it.
Physicist, cellist, former OTTer (1190) resume: https://app.box.com/witthoftresume
(Score: 2) by Fnord666 on Monday June 06 2016, @02:45PM
(Score: 0) by Anonymous Coward on Monday June 06 2016, @03:30AM
The article's description reminds me of holographic lenses or zone plates.
The innovation seems to be in the materials and manufacturing process, not some breakthrough in a new way of bending light.
All the pop sci descriptions make it sound like both manufacturing and fundamental physics.
Your thoughts?
(Score: 2) by takyon on Wednesday June 08 2016, @09:33AM
Can these be used to improve the capabilities of space-based or ground observatories while lowering the cost?
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]