A 100 mW 405nm laser is quite dim to our eyes as it is very close to UV. You would be much better off with a cheap 532nm DPSS laser module. They are very visible even in dim lighting. The beam can also be seen. Most come with a driver attached, so all you really need is a host and a single Li-ion battery to finish one into a pointer. Fasttech sells them for under $5.00 each if you buy a few. I also bought six 200 mW ones years ago, but those seemed to be 200 mW at best, some coming in at 180 to 190 mW.
Hey Paul, any idea where to get circa 200mW 532nm modules nowadays? I have a laser66 pen begging for green lol. Or even a 150mW?
Yes, this is correct. I also believe Techhood has some, or at least claim that.I believe "Aptlightingword" was were he bought his. They still list a few.