445 lasers power underwater

[BennyF]

I totally just read this threads title as "445 lasers power underwear"

 

[Things]

I can't help wondering about where to get a 445nm blocking diving mask.

This will be a wading activity, there is no simple way to heatsink and switch on/off a laser inside a glass container.

Heatsinking may be difficult, but for the switch, use a reed switch and a magnet.

 

[Toke]

Heatsinking may be difficult, but for the switch, use a reed switch and a magnet.

Sure, but not simple to get hold off or install for everybody.

 

[Neptuno]

Heatsinking may be difficult, but for the switch, use a reed switch and a magnet.

well that's the simplest, there is a lot of water to cool down , the LED flashlights take advantage of that, we use a 10000 lumens prototype LED light and is very small, just has to be aluminium
look at this pic La-Jeringa that picture is underwater

 

[anselm]

Hey I have a "couple" of reed switches rated for 1A.
If anyone needs some....
Installation is as easy as soldering two pins.
If that's what Toke meant...

 

[Toke]

I were thinking of not everybody have a soldering iron or know where to connect the wires.
Obviously not the case here.

 

[millirad]

Reed switch would be first choice, or maybe a mercury switch would be ok if used carefully.(Correct angle used)

 

[NetGod3Com]

I believe that glueing the reed switch to the inside of the container and using a Neodymium magnet should work rather well. Just place a small metal plate opposite where the reed switch is to store the magnet, or better yet attach it with a nut tied to some nylon cord.

 

[suiraM]

Looks to me like the 405nm lasers will carry further underwater than the 445nm ones, for a similar amount of power. I would be most interested in hearing how it turns out, as this has been discussed elsewhere for communicating with a rover from the surface (large parabolic collector and narrowband filter with a quadrant sensor at the focal point to track the laser) and one of the concerns has been the problem of getting adequate range.

 

[Neptuno]

I didn't make it go underwater yet, I need to find a good way that will keep the water away from my laser

communication is interesting, I wonder how they do to point the laser in the right spot??

 

[joeyss]

What about a beam expander to get better range?

 

[suiraM]

Won't you just end up trading absorption losses for scattering losses?

 

[Toke]

The ROV on my last vessel handled communication through a fibre optics cable inside the steel cable tethering it. (Along with a 3KV power cable)
Establishing it's exact location were done with some kind of sonar transponder system.

It did have a laser, a green line shining down on the seabed and used to align the assorted cameras as well as helping with distinguishing terrain features.

Like if the line looks curvy it is because the bottom is curvy. The actual terrain survey data comes from a series of sonars.

I don't see any significant advantage* in using laser communication for a rover, you will still need a cable in it, if nothing else then for retrieval when it fails.

*Ok, it would be fun to see if you can make it work.