World first high power underwater handheld laser

[lazeristasUVISIR]

Excellent point---probably true if one were to manufacture it and sell it to the ge neral public within the United States.

Sanwu is in China and no such Laws, rules, or regulations exist there so anything goes and frequently does without restriction

Then only technical problems :wave: Probably cheap and good will not go together going deeper every meter.

 

[Encap]

Then only technical problems :wave: Probably cheap and good will not go together going deeper every meter.

Cheap and good usually don't go together I have to agree, however, both are not absolutes they are relative terms and not necessarily mutually exclusive ---so you have to ask compared to what?

An optimized high power, "dive" laser requires some corrections for optimal beam propagation in an underwater environment as well.

Truth is stranger than fiction--in this case science fiction--a phenomenon which I don't think has ever been mentioned on LPFas follows:
Not many people know that water's focusing effect squeezes a laser beam so that it gets narrower and narrower eventually creating a superheated explosion that can be heard---a very hot little bubble of steam that expands supersonically, makes a shockwave, dissipates a bit and then turns into an ordinary acoustic pulse.

The optical properties of water can be manipulated with very intense laser light to act like a focusing lens, allowing nonlinear self-focusing to take place. At the same time, slightly different laser wavelengths traveling at different speeds in water due to "group velocity dispersion" can be arranged so that a laser pulse also compresses in time as it travels through water, further concentrating the light.

Naval researchers, using modest output pulsed 532nm lasers, have been able to create acoustic pulses of 220 decibels, which is LOUD far exceeding for example the sound of a jet engine at 100 feet of about 140 decibels.

To give you a sense of the scale, the loudest sound NASA has ever recorded was the first stage of the Saturn V rocket, which clocked in at 204 decibels. Another example: a 1 ton/2000 pound TNT bomb acuostic pulse hits ~ 210 decibels 250 feet from impact.

 

[monkeydan]

Awesome. My next laser will most likely brought from Sanwu.

 

[Alaskan]

E n c a p (stupid apple auto correct keeps changing to Uncap)

Thanks for pointing me to this thread, interesting. I wonder if water were used in a short tube which could be fastened to a laser pointer whether anything interesting can be done with it.

 

[Encap]

E n c a p (stupid apple auto correct keeps changing to Uncap)

Maybe turn off auto-correct and let your mind correct as you go--much faster and much better than any auto-correct program you let speak for you. Am sure all it is a matter of is doing it yourself for a week or two and then smooth sailing.

I have all the auto-anything programs turned off on my computer---they were more annoying than helpful.

 

[Alaskan]

Great info

Not exactly. In 1963 a low-loss “optical window” of undersea communication for blue-green lasers between 420–532 nm was discovered. Since then research has not stopped. Blue/green laser light has the best transmissivity through water, however, some systems employ 635nm for underwater use in limited well defined applications with a few types of sensors.

The reasons that there aren't many applications of lasers in an
underwater environment is associated with the way light is transmitted
underwater.

There are two distinct causes for the energy loss of a light signal in seawater:
one is absorption and the other is scattering - 2 separate problems:

A. Most light is absorbed by water -- Water absorbs ultraviolet,
yellow and red and infrared radiation very strongly, so that beams in
these spectral regions cannot be transmitted very far -- meaning that
systems using such lasers are pretty useless. On the other hand, water
(seawater, that is) transmits blue-green light pretty well -- losing
"only" about 5% of its original intensity for every meter it transmits
through water.

B. There are often little specks of dust, tiny animals
(phytoplankton), and tiny plants (photoplankton) in water, and these
reflectd a little bit of the light, too, reducing intensity as it passes
through water. This adds to the problems noted above in Item A.

The effect of these two effects is that lasers used underwater have to be
much more powerful than those used in air, where absorption is generally
much lower than in water.

The above having been said, lasers have been used for underwater applications for quite some time.

One successful use of lasers is a laser system that provides underwater sensing -- a kind of laser radar:
Blue-green lasers located in airplanes are sometimes aimed
so that they go straight down into water that the planes are flying over.
Using very sensitive detectors in the airplane, the system detects the
small amount of light reflected both from the surface of the water and the
bottom of the harbor. This allows measurement of the water depth to
accuracies of a foot or so. The big advantage of such systems is that
they can collect data very quickly, because the airplane moves very
quickly and the lasers can be pulsed at a high rate. One example of this
is the use by Australian government planes of such a system to map their
very large coastal areas -- it's much quicker and cheaper to use a laser
radar to do this than it is to use conventional acoustic (sound wave)
sonars to make such measurements from ships.

Another laser system which is used underwater uses blue-
green lasers to communicate from airplanes to submarines. As early as
1983, experiments were done which demonstrated that this could be done
sucessfully. Investigated successfully also were satellite to submarine communications
using blue-green lasers which not much has been published about for obvious reasons.

Beyond this, there haven't really been too much uses of lasers
underwater. Bob Ballard -- the man who mounted the expeditions that found
the Titanic in the North Atlantic Ocean -- expressed some interest in
trying to use blue-green lasers to assist in taking pictures of the
Titanic, but found out that development of an appropriate system would be
very expensive and not too much better than just using high power
spotlights... which he ultimately used instead of lasers.


For more information see Electromagnetic Absorption by Water here:
https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water

A more detailed information with great graphics, see: Water absorption spectrum

Technical article: Absorption and attenuation of visible and near-infrared light in water: dependence on
temperature and salinity here: ftp://misclab.umeoce.maine.edu/users/optics/classFTP2015/Labs/Lab2_resources/Pegauetal1997.pdf

Interesting paper from 1983 on military applications of blue-green lasers:
http://www.google.com/url?url=http://www.publications.drdo.gov.in/ojs/index.php/dsj/article/download/6173/3278&rct=j&frm=1&q=&esrc=s&sa=U&ved=0ahUKEwjYu7OiydHPAhVDPD4KHVCEBVs4ChAWCBowAQ&usg=AFQjCNGGhfUkWXE-TJQjZqO7Y5W_Mr63EQ

Good site on Ocean Optics see: Inherent Optical Properties ? Ocean Optics Web Book

 

[BobMc]

@Podo, was wondering if you have a release date or when we might expect one? Thanks

 

[Dr_Evil]

Any idea when they will be available for purchase?

Typical classifications for wristwatch water resistance are as follows:
Water Resistant 3 atm or 30 m: Suitable for everyday use. Splash/rain resistant. Not suitable for showering, bathing, swimming, snorkelling, water related work and fishing.
Water Resistant 5 atm or 50 m: Suitable for swimming, white water rafting, non-snorkeling water related work, and fishing. Not suitable for diving.
Water Resistant 10 atm or 100 m: Suitable for recreational surfing, swimming, snorkeling, sailing and water sports. Not suitable for diving.
Water Resistant 20 atm or 200 m: Suitable for professional marine activity, serious surface water sports and skin diving.
Diver's 100 m: Minimum ISO standard (ISO 6425) for scuba diving at depths not suitable for saturation diving.
Diver's 200 m or 300 m: Suitable for scuba diving at depths not suitable for saturation diving.
Diver's 300 m to 1000 m +: suitable for mixed-gas diving.

The watch I wear is uspposedly rated for 30m. I have worn it in the shower and gone swimming with it on multiple times. It hasn't had a problem yet.

 

[Nutball]

Any more experiments with under water lasers?

 

[hakzaw1]

sorry for necro but..
are you sure this laser came out BEFORE JETLASERS Yamataka?? which is 1W 520 so high power and its waterproof.. there si a YTube video of it in fishtank -- am betting that guy in the vid declined to test it under water in the stun mode--OUCH!!!!.
I am in agreement that being declared waterproof for me just means safer to use outdoors when raining WHICH looks super and makes for a good sweeping beam pic. Or if one fell overboard... God forbid..

some VERY interesting posts here _ + rep for the house...

 

[Encap]

sorry for necro but..
are you sure this laser came out BEFORE JETLASERS Yamataka?? which is 1W 520 so high power and its waterproof.. there si a YTube video of it in fishtank -- am betting that guy in the vid declined to test it under water in the stun mode--OUCH!!!!.
I am in agreement that being declared waterproof for me just means safer to use outdoors when raining WHICH looks super and makes for a good sweeping beam pic. Or if one fell overboard... God forbid..

some VERY interesting posts here _ + rep for the house...

Hak : This laser has not come out yet--probably never will due to very limited market.

If you look at/read post #1 you will notice it is a laser designed for underwater use as in scuba diving.

 

[Dutch67]

Yeah I gave up hope on this one. Every time someone brings it up there seems to be no response as to whether it was still in progress. I just assume they didn't have the time to develope it to a marketable stage.

A shame really as I'd love to have one. I live very near the ocean and it would be awesome to take one out with me

 

[BobMc]

I did hear from Podo about a month and a half ago, he said it was still being researched. They have one completed laser that is being run though the paces. So I'm still hopeful that it will be built. Keeping fingers crossed.

 

[Nutball]

It will be the next shark attack life saver

 

[Rivem]

This is definitely a neat laser. If I was still in a decent area for diving, I'd like one in 520nm or maybe 638nm though. The blue just doesn't seem to scatter and stand out enough. Blue transmits more effectively, but that leads to a lot of blue light in the background and less light coming back to see. Something that doesn't transmit as well would probably have a much more visible beam for a shorter distance.

405nm is great underwater to play with fluorescence, so definitely a version to consider. No idea how visible it'd be though.

 

[AMooMooCow]

If anyone is going to use this in a swimming pool when they get it, make sure you wear your glasses without exception. When taking this profile pic, the water was way choppy, and the beam was dancing all over the place; it'll b the same under the surface. If you have a round swimming pool, it will reflect into your eyes. I would also like to see how quickly one of these can burn into a pool lining, because the effect of convection of the water should help reduce local heat, but the radiation is very localized. Anyone willing to sacrifice their pool? For science.