I bought some 532nm green lasers for eight dollars to make an array with, here's a photo. I think they might be the same thing as the ebay G301, but with a different host. Can you tell me if the laser module inside is the same as the one in this photo?
I bought a large number of them, most are in the 50-70 mw area for output, some lower, some higher. The performance can vary quite a bit from unit to unit, a couple of them would not begin lasing for a few seconds, but not many like that.
Overall testing results for power output:
(Note: These units do not have IR filters which means the output power I measured is part IR and part 532nm, I don't know the ratio between them yet but will test later with an IR filter to determine how much is 532nm.)
Watching the power output some would start at 40-50 mw and then as they heated up would go to 70 mw or more, then slowly trail back down in power to 40 mw. Others were stable with 70mw output from first turn-on for 10 minutes without much change in power. Some would immediately produce 70mw or so and then over a period of a few minutes slowly ramp down to half power. Out of the twenty I have tested so far, three of them would put out over 100mw (after waiting 30 seconds or more for my power meter to stabilize, or the units themselves to stop changing output power) and were fairly stable at that output for a few minutes.
This from a sampling of about 20, I have another 50 to test. Although the majority of them put out about 50 to 70mw, not many of them would hold that 70 milliwatts for more than a couple of minutes before the power would start to slowly ramp down.
Of the units tested which did not come on at their full power output, I could see the brightness ramping up to higher levels as time passed, so I think most of them which acted that way are taking awhile to come to temperature for a more efficient output. Also, since some of them would come on at their full brightness when first turned on and then slowly reduce in power, it is my belief that the performance and temperature sweet spot of the crystals used in these lasers can vary from unit to unit by quite a bit. However, considering they don't have crystal heaters inside to keep the crystal at their individual optimum temperatures to consistently produce the most output over time, I think these cheap units are fairly stable for what they are. I believe I will likely end up using just the modules from the units and have a large number of hosts available to sell from them.
Here's a link to one sellers listing on ebay:
http://www.ebay.com/itm/5Mile-Range...Visible-Beam-Mark-Direct-150-US-/141147727954
