Underwater Lasers

[justacaveman]

If you used a green laser underwater that was powerful enough to be used as a weapon, what would the actual result be?

Would the laser flash heat the water in it's path, making it completely useless as a weapon and a danger to the operator?

Would the laser actually work just fine?

Or some other result?

:?

 

[DFW]

If you used a green laser underwater that was powerful enough to be used as a weapon, what would the actual result be?

Would the laser flash heat the water in it's path, making it completely useless as a weapon and a danger to the operator?

Would the laser actually work just fine?

Or some other result?

:?

Door #1

 

[rust]

If you used a green laser underwater that was powerful enough to be used as a weapon, what would the actual result be?

A blue-green laser used underwater would have a much reduced range,
and it would also cause much less damage, with range and damage de-
creasing with the amount of mud in the water.

Whether the heating of the water would become a problem would mainly
depend on the power output of the laser. A portable laser should cause
no serious problem, a starship laser certainly would.

Underwater lasers are currently used as short range sensors (LIDAR) as
well as for short range communication, because they are one of the ve-
ry few possible alternatives to sonic devices.

Edit.:
Old, but still true: http://www.madsci.org/posts/archives/jun99/927916034.Ph.r.html

 

[justacaveman]

I've seen the blue-green lasers used as sensors, and noticed that the beam was easily visible. My concern with a weapons grade laser was that there would be so much side-scatter to the beam that it would release a tremendous amount of heat right in the user's face.

Is there a laser frequency that would pass invisibly through water, yet still be useful as a weapon?

 

[rust]

My concern with a weapons grade laser was that there would be so much side-scatter to the beam that it would release a tremendous amount of heat right in the user's face.

A weapons grade laser would almost certainly use millisecond pulses to
avoid most of that problem, but a very powerful laser would probably
still be quite dangerous for the user, too.

Is there a laser frequency that would pass invisibly through water, yet still be useful as a weapon?

As far as I know, blue-green lasers are the only ones that work underwa-
ter, at least I have been told that IR- and UV-Lasers do not work there.

 

[DFW]

Is there a laser frequency that would pass invisibly through water, yet still be useful as a weapon?

I can confirm that the US Navy has only found the BG wavelength to be able to penetrate water to any acceptable degree. Even then, its range is limited and it scatters quickly.