LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))

[Mark Green]

I don't know a lot about data transmission, my main application is display.
The mathematics behind data transmission and display are similar, they are
based on wave propagation and diffraction and lots of Fourier transforms.
The laser power is not overly important, it's the resolution of diffraction
pattern or hologram that you produce.  It's a very redundant coding scheme,
so part of the signal can be lost and you can still recover all the
information.

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Swift
Griggs
Sent: July 19, 2016 6:04 PM
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: RE: LASERS! && Freemont Street LED array (was Re: Cray J932SE (was
Re: Straight 8 up on Ebay just now))

On Tue, 19 Jul 2016, Mark Green wrote:
> In my day job I work on computational holography and other forms of 
> esoteric 3D displays, so I can give you some insight in how these 
> things work.

Holography is amazing. Do you know much about so-called "free space optical"
data transmission? I worked with some gear a few years ago that could
transmit & receive using multiple lasers at 1Gbit. I was fascinated with
that stuff, but the vendor had their folks do all the alignment and
installation. So, I didn't get to work with it much.

I wonder if you've seen faster speeds than that. I also wonder what the
power levels look like for those lasers and what distances the really
serious ones can reach. Can they still work in bad weather? It seemed like
the ones that I mentioned, still worked in the rain.

-Swift

PS: It was the May 1984 National Geographic cover that blew me away and made
me forever respect holography. :-)


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