[Laser] NLOS Optical Comms

[KY1K]

>  an experiment
>to study upper atmosphere air flow at the University of Illinois.  We used
>a rhodamine 6G dye laser, which excited the "D" lines of sodium in the
>upper atmosphere.  A telescope with a Fresnel lens about 1000 feet away
>used a photomultiplier tube to detect the returned light from the sodium.

Please tell us more-

How much power output did the laser have? What wavelength gave good 
returns? Is this mode only usable with backscatter, or is it possible it 
might support some other reflection angles and be usable over a 'real' comm 
range?

What size lens did you use to collect light? If your receiver was 
co-located, did you have QRM problems or did you have to listen for the 
beat frequency (doppler frequency)?

Please tell us more-

Thanks,

Art