Laser that is clearly visible on snow?

[pylsa]

I need a laser light that is clearly visible on snow on a low light/cloudy day. What color would be best? And how strong must the laser be to be clearly visible from about 5-8 meters? And can i use a tinted glass in a goggle to increase the intensity of the light? Also I would like it to be a grid or a cluster of dots, would a lens do that, or do they weaken the light to much?

And do you have any suggestions to what i might buy to test it out? (Needs to be portable).

 

[ARG]

Almost all lasers are extremely visible on snow because of the albedo.

50mW of 532nm would be ideal, though I don't recommend 532nm since you're using this in cold conditions.

A single mode 450nm Osram diode would probably be best, or a single most 638nm diode.

 

[DrSid]

Green would be most visible in most scenarios. You want just the dot to be visible, or line ?
In any case .. problem is, if you want to have dot visible during day, I think 5mW would not be enough. You would need more like 50mW, or even more. And anything over 5mW is not eye-safe. OF course, only in case of beam hitting the eye directly. But such risk always exists, and all regulations are pretty strict about it.
So people around would have to wear special goggles .. for protection .. not to make the dot more visible, but to make it a lot LESS visible - thus safer.
Which generally means, that laser are not very useful for signaling and pointing in well lit conditions.

 

[Bob_Boyce]

Almost all lasers are extremely visible on snow because of the albedo.

50mW of 532nm would be ideal, though I don't recommend 532nm since you're using this in cold conditions.

A single mode 450nm Osram diode would probably be best, or a single most 638nm diode.

I second that. My single mode Osram PL450B build looks really great on the snow. It can handle the cold well too, unlike most greens. I bought my 450nm modules from DTR

https://sites.google.com/site/dtrlpf/home/diodes/450nm-pl450-diodes

Bob

 

[pylsa]

Thanks for all your replies, it has been very helpful.

I know now that it should be about 50mW with a 450nm Osram diode.

Two points that is still a bit unclear.

1. Tinted goggles. Protective gear will reduce the light BUT can I increase it, in order to make the light less harmful to others. For example could i get 5mW to look like 10mW through a special tinted glass?

2. Grid or cluster, dots or lines. I would like it to be in some kind of grid with a spread of ca. 2x2 meters at a distance of 4 meters. Is there any lenses that does this and how would it effect the intensity of the light?

 

[DrSid]

As for tinted goggles, green colored goggles will dim all colors except green, so it could make green stand out a bit more. At least some cheap red laser water levels use this mechanism. Problem is it does not work much.

 

[ZeroLaser]

pysla,

I am fairly new to this hobby and I have never used one myself, but from what i have read on the forums..... something called a "diffraction grating" certainly seems to fit your problem of creating a grid of dots.

http://laserpointerforums.com/f39/diffraction-gratings-22685.html
http://laserpointerforums.com/f49/h...ating-affect-radius-intensity-dots-49310.html