# A breakthrough in lenses **URL:** \ **Category:** In My Humble Opinion\ **Created:** [June 3, 2016, 1:59pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386 "2016-06-03T13:59:45Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 3, 2016, 1:59pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/1 "2016-06-03T13:59:45Z")
> **[Flat lens promises possible revolution in optics](https://www.bbc.co.uk/news/science-environment-36438686)** > > A flat lens made of paint whitener on a sliver of glass could revolutionise optics, its US inventors say. > [@](#): > > The lens is quite unlike the curved disks of glass familiar from cameras and binoculars. Instead, it is made of a thin layer of transparent quartz coated in millions of tiny pillars, each just tens of nanometres across and hundreds high. > [@](#): > > “Once you have the foundry - you want a 12-inch lens? Feel free, you can make a 12-inch lens. There’s no limit.” What does this mean for telescopes? ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [June 3, 2016, 2:30pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/2 "2016-06-03T14:30:20Z")
Most professional telescopes don’t even have lenses, they use mirrors to concentrate the light instead. However, since this approach would make the lenses far lighter (eliminating lense sag) and apparently you can tune it to allow far shorter focal lengths then currently possible you could have some fantastic wide angle images available to people. You could, maybe, get a cool inexpensive refractor equivalent to a dobsonian. ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [June 3, 2016, 3:04pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/3 "2016-06-03T15:04:05Z")
Right now with cheap image sensors and lenses there’s no shortage of cheap, compact, but incredibly shitty microscopes. But if these metalenses are as good as the hype implies, you might be able to get a cheap and compact microscope with resolving power approaching that of a good research grade compound microscope. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [June 3, 2016, 3:46pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/4 "2016-06-03T15:46:53Z")
> [@Quartz](#): > > What does this mean for telescopes? I’d imagine that it means that you’ll see some REALLY spiffy eyepieces based wholly or in part on this technology once it’s commercialized. Plus, for Schmidt/Maksutov-Cassegrain telescopes, you could make better front corrector plates, I’d think. I wonder if it would be handy for big refractor objectives without crazy long focal lengths. How cool would it be to have a 200mm f6 refractor? ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 3, 2016, 3:50pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/5 "2016-06-03T15:50:32Z")
> [@Grey](#): > > Most professional telescopes don’t even have lenses, they use mirrors to concentrate the light instead. Well yes, but imagine if you could use this to concentrate the light instead. Have a honeycomb 10 metres in diameter focusing down - in a way you cannot achieve with glass - to a single detector. Would this not make telescopes much lighter? ---
**Author:** ![MindsEye\_Watering](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindseye_watering/32/3619_2.png) [@MindsEye\_Watering](https://boards.straightdope.com/u/MindsEye_Watering)\ **Post date:** [June 3, 2016, 4:01pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/6 "2016-06-03T16:01:21Z")
> [@Quartz](#): > > [Flat lens promises possible revolution in optics - BBC News](http://www.bbc.co.uk/news/science-environment-36438686) > What does this mean for telescopes? Thanks for this. This is REALLY cool! ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [June 3, 2016, 5:30pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/7 "2016-06-03T17:30:27Z")
> [@Quartz](#): > > Well yes, but imagine if you could use this to concentrate the light instead. Have a honeycomb 10 metres in diameter focusing down - in a way you cannot achieve with glass - to a single detector. Would this not make telescopes much lighter? Maybe, but I think the improvement would be better applied to space telescopes. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 3, 2016, 6:08pm UTC](https://boards.straightdope.com/t/a-breakthrough-in-lenses/756386/8 "2016-06-03T18:08:58Z")
> [@](#): > > “Once you have the foundry - you want a 12-inch lens? Feel free, you can make a 12-inch lens. There’s no limit.” There may be no theoretical limit, but there is a practical limit. They are using semiconductor fabrication techniques, and currently, the largest standard wafer size is 12 inches. Which is probably why he happened to mention that size. For anything larger, they’d need to build a new foundry with all new equipment to handle the larger wafer size. It _is_ possible to make a telescope out of multiple mirror segments, like the [Keck telescope](https://en.wikipedia.org/wiki/W._M._Keck_Observatory). But it’s very difficult, because the segments need to be aligned to a very high precision (order of several microns). Making a telescope out of metalens segments would be _more_ difficult - they need to be aligned to the same accuracy, but because they are lenses, you can’t have a support structure behind it. Also, the metalens may have perfect on-axis performance, but there may be a limit to how much off-axis aberration it can correct for. A perfect parabolic mirror has perfect on-axis performance (i.e. if you point it directly at a star, it will form an infinitely small spot, limited only by diffraction and external factors such as the atmosphere), but it has off-axis aberration (coma). I suspect a metalens will have the same limitation, and it will take at least 2 metalenses to make a telescope with a reasonable field of view.