Quote Originally Posted by Kirk Keyes View Post
Blu-Rays use LASER diodes at 405 nm - funny thing is that is considered a "violet" wavelength!
It is. Moreover, in contrast to what the eye sensitivity curve suggests, these lasers are highly (painfully) visible!

Quote Originally Posted by Kirk Keyes View Post
I see Sony unvieled a Blu-Ray prototype in Oct. 2000 - I'm not sure when the diodes were invented, but it's certainly a few years before they showed the Blu-Ray.
Meanwhile these lasers have become pretty cheap and are available with powers >1W. I assume they might be interesting for photographic applications involving the use of dichromates or ferric salts etc.