635nm Vs 650nm

Is there a noticeable difference? I have a few cheap red laser pointers and modules. Is it likely any of them are 635nm? What about DVD burner red diodes? :-?

Thanks
-Nick

side by side you can see the difference in wavelength. 635nm diodes are more expensive mW for mW than the 650nm diodes. You can also get 650nm diodes in higher powers. DVD systems are the 650nm diode.

It is possible for cheap pointers to be 635nm. The class IIIa warning label might indicate the exact wavelength although some give the entire red range as the operating wavelength.

It is unlikely you have any 635nm pointers.

635nm would be a lot brighter compared to a 650nm if you had them side by side, if you had just one of them then the difference would be barely noticeable.

I noticed that the laser crabs that maplin sell use 635nm red lasers.

My Helium Neon laser is listed as 632.8nm on the warning sticker.  It's <5mw, and when its spot is held next to one from my 650 pointer, it looks a lot closer to the orange side of red.  As the wavelength shortens, it moves toward the orange-yellow side of the EM spectrum, as it lengthens it moves toward near the dark red-infrared region.

-Brett