Green laser on speargun

[foxfish]

Always a controversial subject but I am always trying to develop new ideas & although lasers are not a new idea, one that works would be very interesting to me.
I am led to believe that a blue laser is the most successful for penetrating bright conditions?
Interesting that red & green (the type & power generally available) just dont work in our locale sea at least not in the day time but even a cheap red pointer shows up very well underwater in the dark.

 

[sancarlos]

From the theoretical standpoint we should consider the overall optical system performance, not just isolated element.
In this case system consist of laser+eye. So we need take into account the spectral sensitivity of an eye as well as absorbtion spectrum of the water. You right and green of 532nm (green lasers) is absorbed almost twice faster then blue laser (I think it is around 470nm), but human eye is almost twice more sensitive to green then to blue of those wavelengths.
So both effects are cancelling each other. BUT! We also need to concider the sun light since it is illuminating the target and produce the noise in our case, which makes the target recognition harder. And you got me on the paradoxal thought here. To make the laser dot more visible it might be benefitial to use red laser, not the green one since there is a lot of green illumination deep in the water, but almost no red! I need to do more research on that. So it just might be that in this particular application red might be better solution for optimal system performance, contrary to the initially obvious green laser.
Thanks for the great comment!

 

[Cammo]

Hey Sancarlos,

GREAT thread....I have a laser I bought ages ago...a cheapie...to do the same experiment....but was just going to tape it on, haha. I think a lot of people are interested in your project, but few (i.e. me are willing to invest the time!). Many fear new technology...but who goes boating without a sounder and GPS these days? and in the end nothing will replace experience and bottom time!
Hunt wisely and take only what you need is the key ;-)