
First Optical Rectenna Converts Light Directly to DC Current - jcr
http://www.news.gatech.edu/2015/09/28/first-optical-rectenna-%E2%80%93-combined-rectifier-and-antenna-%E2%80%93-converts-light-dc-current
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hliyan
RF rectennas apparently already have efficiencies up to 90%. According to this
article, improving the fabrication process could lead to optical efficiencies
up to 40%. That's double the efficency of any photovoltaic cell available
today.

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mapt
Not all variants.

[https://en.wikipedia.org/wiki/Solar_cell_efficiency#/media/F...](https://en.wikipedia.org/wiki/Solar_cell_efficiency#/media/File:PVeff\(rev150806\).jpg)

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magic_man
I thought they already had photo voltaic cells. I guess this is just a more
efficient version of a device like that. It made it sound like they had
invented a photo voltaic cell which they didn't.

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hatsunearu
This is huge because it has potential (hah) to become an ultra high speed
photodetector, which have numerous uses in the industry.

Conventional photodetectors are essentially transparent photodiodes, and you
have to pass a constant current through them for them to work, which generates
heat and is generally a bad side effect.

Antennas on the other hand are completely passive and therefore immune to heat
related issues. Also, unlike photodiodes and semiconductor devices, antennas
are completely linear. Nonlinearities cause distortion that limit usable
bandwidth.

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unwind
Lots of dupes of this story recently,
[https://news.ycombinator.com/item?id=10305226](https://news.ycombinator.com/item?id=10305226)
seems to be the oldest but there are a few more.

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dang
In addition to jcr's thorough response, I'll add that we don't officially
consider reposts to be dupes until the story has had significant attention
here. Otherwise the randomness of /newest is too brutal. I wrote about this
here if anyone is interested:
[https://news.ycombinator.com/item?id=9828818](https://news.ycombinator.com/item?id=9828818).

