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It's highly probable that DX's 5mw offering is dangerously overspec. True <5mw lasers are very rare.

To be frank, the fact that you're asking questions about wavelength indicates that you're in over your head and don't have the background to have a reasonable chance of pulling this project off. Laser communications is more a matter of electronics and optics hardware than programming. Your...

By the math, the eye is about 180 times more sensitive to green than to 405nm violet. However, atmospheric Rayleigh scattering will reflect 405nm about twice as effectively as it will reflect green. Theoretical beam visibility for 405nm, therefore, is about 90 times worse than for green. 5mw...

Not easily done. Cutting/ignition/'burning' power is a function of both laser wavelength and the reflectance of the target at that wavelength.

Quality control at DX, FocalPrice, and the other cheap and diverse Chinese exporters is poor to non-existent. There is considerable variability between individual examples of the same product that it's impossible to say if any given laser will be good or a dud. You're much better off to spend a...

Current best knowledge in this area comes from: Sharpe, L. T., Stockman, A., Jagla, W., & Jägle, H. (2005). A luminous efficiency function, V*(λ), for daylight adaptation. Journal of Vision, 5(11):3, 948-968, Journal of Vision - A luminous efficiency function, V*(λ), for daylight adaptation...

405nm is far outside of the color gamut that normal imaging devices can represent. Cameras and monitors can't reproduce 405nm; how 405nm appears is undefined and is largely up to chance.

No, even in completely clean air, some portion of the beam will be visible as a result of Rayleigh scattering from air molecules. Rayleigh scattering is wavelength dependent, however, and will benefit shorter wavelength lasers most. At extreme power levels, beams can be made very visible due...

The FDA is accepting lasers which meet IEC standards as legally acceptable. IEC rules are less stringent than their CFR counterparts. Earlier CDRH guidance indicates that shutters and emission indicators are not required for Class 2 and 3a devices under certain circumstances. Laser Products -...

Beware that most of the Chinese '5mw' offerings are actually much more powerful than claimed. For example, some of Ledshoppe's 5mw pointers had a measured output of over 40mw. DealExtreme is also extremely bad for highly overspec pointers. If, for safety or legal reasons, you want a pointer...

No, Canada. On the west coast.

Just received a laser from Rayfoss. Ordered 4 Nov, was shipped out on 6 Nov, received on 14 Nov.

Get a <5mw laser if you want to play around like this. Beams will reflect and refract unpredictably from irregularly shaped objects. Redirected beams from high powered lasers can easily blind you.

I've never dealt with Information Unlimited but they have been in business for ages--since the late 1980s at least. They were the 'go-to' place for oddball & dangerous tech toys in the pre-Internet era. Presumably they're doing something right to have stayed in business this long under the same...

Don't assume that goggles rated for 532nm will block 1064 or 808. When using high power lasers without IR filters, you must use goggles rated and certified for both the green and IR emission lines.

According to which luminosity function? I get 69W using CIE 1924 and 8.7W using Sharpe et el.

You'll need about 69 WATTS of 405nm to match the brightness of 50mw 532nm green. Matching 200mw of 660nm red will take 19 watts.

Long term update: After trying and failing to open the host, I discovered a 1mm x 4mm ball of lint (?) in the front end of the pointer. Removing this corrected the issue with beam quality changing as the pointer orientation changed, but the beam quality is now uniformly bad (ugly smeared blob)...

Focalprice 5mw 650nm pointer reviewed: http://laserpointerforums.com/f52/review-focalprice-sku-08ebr24e-5mw-650nm-44109.html

Long term update: I have had a few minor problems with intermittent operation and flickering due to what appears to be a flaky switch. Sometimes the laser has to be turned on twice in order to light up. These problems effect perhaps 1 out of every 25-50 uses and are a minor inconvenience at...