Navy Scientists Develop Laser For Underwater Communication

Researchers at the Naval Research Laboratory claim to have come up with a better tool for underwater acoustics. The new system uses laser light to create sound underwater from a distance. This technology could allow planes a much easier method of communicating with submarines without the need for a floating buoy. "Efficient conversion of light into sound can be achieved by concentrating the light sufficiently to ionize a small amount of water, which then absorbs laser energy and superheats. The result is a small explosion of steam, which can generate a 220 decibel pulse of sound. Optical properties of water can be manipulated with very intense laser light to act like a focusing lens, allowing nonlinear self-focusing (NSF) to take place. In addition, the slightly different colors of the laser, which travel at different speeds in water due to group velocity dispersion (GVD), can be arranged so that the pulse also compresses in time as it travels through water, further concentrating the light. By using a combination of GVD and NSF, controlled underwater compression of optical pulses can be attained."

Re:underwater lasers?

[Bovius]

I think editor was just digging for shark comments on this one.

Whale/sonar people are going to love this one

[BigSlowTarget]

I don't know how the audio volume of this system compares with sonar systems (though the article's 220db and 160db from http://www.oceanmammalinst.org/mgpaper.html kind of gives clues and weakly suggest might be as much as 64x), but I suspect the people who oppose the use of sonar by the navy on the theory that it hurts whales are going to go nuts over this one.

There is no where near enough info to actually assess any kind of threat, but I'm sure the panic button will be hit anyway.

Re:Whale/sonar people are going to love this one

[ibsteve2u]

Need a moderation tag for "Informative, yet sadly obvious.".

Re:Operational security?

[canadian_right]

Nothing.

Obviously you don't communicate directly with subs during hostilities using methods that can be easily overheard.

Why do so many slashdotters think that experts have not thought of their brilliant insight many years ago?

Re:Whale/sonar people are going to love this one

[anotherhappycamper]

I hope it does push the panic button. It is one thing for us to defend ourselves. It is quite another for us to make another species miserable or extinct while attempting to optimize a way to defend ourselves from our own fears. Public outcry and discussion can give us pause so that we can investigate whether the effectiveness outweighs the possible ethical costs, and hopefully come up with a thoughtful solution.

Re:Whale/sonar people are going to love this one

[woolpert]

Who, exactly, are you willing to kill / let die to achieve your goals.