- Nov 21, 2009
Thanks Paul! I am glad the 650 worked out for you! When I decide to do the measuring I will try a number of my 532nm lasers. At this point, I have about six or seven of them. I hope that is enough!!!You cannot trust the cheapest 532nm lasers as I have two that do multiple lines. One has four lines and the other has six. They are spaced about 4nm apart. That being the case, it is possible to get one that lases on a different line than 532.14nm. I would use a more expensive laser to use as 532nm. I have one that does 1350 mW that is spot on.
It is true that the main line is 532.14nm, so lasers like this tend to lase close to that line. But, it isn't something you can depend on.
BTW, I got that 650nm laser and it measures 211 mW. It states on the label <200 mW, but that is obviously not the case with mine. Not too shabby for $10.00.
Also, there have been many threads over the years showing how to measure wavelengths with a diffraction grating. Before I got my first spectrometer, I bought a 1000 l/mm piece of transmission grating about 12 inches by 8 inches. I used to cut pieces off of it to measure wavelengths. But, to get the most accurate measurement you need to use a tape measure and set it up to be about at least 15 feet away from the surface you will be measuring the 1st order maxima on.
For comedy's sake I should add that a couple of my 532nm lasers were very expensive. One which is 8mw cost 900 dollars back in the
days when they were exotic. I remember when 532 nm 5mw pens were 250++. The new stuff is much better...but all of my old stuff is properly filtered for IR. Unlike the ebay specials of today.