Researchers Construct a Telescope with a Flat Lens


The image of the Moon within the banner may not look all that spectacular, however it’s completely astounding from a technical perspective. What makes it so distinctive is that it was taken through a telescope utilizing a totally flat lens. This sort of lens, referred to as a metalens, has been round for some time, however a workforce of researchers from Pennsylvania State College (PSU) not too long ago made the biggest one ever. At eight cm in diameter, it was massive sufficient to make use of in an precise telescope – and produce the above image of the Moon, nevertheless, blurred it is perhaps.

Metalenses have been produced earlier than, however sometimes solely on a millimeter scale. They make the most of nanostructures etched into the floor of the lens itself, forcing the sunshine that passes via them to a central point of interest, a lot because the curved floor of a typical lens utilized in optics does. A part of the explanation different metalenses have been comparatively small in scale to date is the issue of making these nanostructures on a bigger lens construction.

For this, the workforce at PSU turned to another manufacturing course of – deep ultraviolet (DUV) photolithography, a course of sometimes used to create high-speed laptop chips. In comparison with the standard metalens creation means of electron beam lithography, DUV has a number of benefits.

Right here’s an argument for the significance of metalenses.
Credit score – TEDx Talks YouTube Channel

First, it’s repeatable at excessive velocity. The workforce, led by Dr. Xingjie Ni, did what all good downside solvers do. They took a big downside – on this case, find out how to cowl the floor of a 4 cm circle with nanostructured antennas – and broke it down into manageable chunks. These chunks turned out to be 22 mm x 22 mm areas of the plate, they usually then patterned the required antenna constructions onto the lens utilizing a DUV system at Cornell.

A second benefit is DUV is able to persistently producing small particulars. That is very true when it’s used to create transistors on a pc chip, however on this case, the nanostructured antennas could possibly be produced with the identical stage of precision.

That isn’t to say your entire analysis course of was so simple as working a brand new system to create a bigger model of a recognized expertise. The researchers needed to considerably shrink the file measurement used to direct the DUV machine on find out how to function. They did so through the use of information approximations and different file compression strategies.

The PSU analysis workforce shows their metalens. From left to proper – graduate college students Lidan Zhang, Shengyuan Chang, Md Tarek Rahman, and professor Xingjie Ni.
Credit score – Jeff Xu / Penn State

Even with all that effort, challenges stay – probably the most notable being chromatic aberration. Chromatic aberration happens when completely different colours of sunshine are bent by the nanostructured antennas otherwise. This creates completely different focal factors for various colours of sunshine, inflicting them to blur if collected in the identical picture. However Dr. Ni and his graduate college students are working exhausting on designing a brand new and improved system that would eradicate the chromatic aberration downside and different optical points attributable to the flat floor.

Nevertheless, astronomy isn’t the one sensible software for these bigger metalenses. Regardless of their ubiquity, the lenses of a cellphone’s digicam are nonetheless curved, which takes up priceless area in its design. Usually, you may see a protuberance close to the digicam lens on the slimmest cellphone fashions. With a real metalens that works as meant, these points could possibly be eradicated, main to an intensive set up base if cellphone producers develop into . Each newbie {and professional} astronomers would most likely get some a lot better footage of the Moon out of the deal as effectively.

Be taught Extra:
PSU – Flat, pancake-sized metalens photos lunar floor in an engineering first
Zhang et al – Excessive-Effectivity, 80 mm Aperture Metalens Telescope
UT – Christiaan Huygens’ Telescope Lenses Inform Us He Was Nearsighted
UT – What are Telescopes?

Lead Picture:
Picture of the moon captured with a telescope using the brand new, bigger metalens.
Credit score – Xingjie Ni

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