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365nm LEDs don't cost thousands of dollars. 355nm and 375nm laser diodes do. (365nm laser diodes are not available.) Humans can see 365nm. According to CIE1931 our photopic (color) sensitivity goes like this: 360 0.000003917000000 365 0.000006965000000 370 0.000012390000000 375...

Thanks for the replies. Actually I'm curious about the range of vision in general with respect to wavelength. So far three different types of vision have been documented: photopic vision (cones), scotopic vision (rods), and mesotopic vision (both rods and cones in moderately dim light). However...

I just left a comment on YouTube about the dangers of looking at the dot. Most people don't even know about that. I learned it here on LPF.

780, 808, 980, 1064, 1342? Sensitivity of the human eye when viewing ordinary objects illuminated by a standard lamp simulating northern daylight at midday at 45° N latitude. scotopic (night) vision nm sensitivity 380 0.000589 385 0.00111 390 0.00221 . . . 500 0.982 505 0.998 507 1.00 510...

Thanks for the tips. 555nm sounds great, since that's the peak sensitivity wavelength of human color vision, as well as the wavelength at which lumens are measured. I also appreciate all the tips about 670nm laser diodes, as it looks like I'll probably build my own. I just feel sorry for the...

You seem to be confused as to what this thread is about. It's not about laser diodes, 670nm or otherwise. It's about documenting the demise of the 670nm laser pointer for historical research purposes. Apparently this particular variety was "the Ford Model T of laser pointers," i.e., not the...

I saw the eye doctor (ophthalmologist) earlier this month and was diagnosed with incipient cataracts and macular degeneration. Apparently everyone gets this as they get older. Some people just get it earlier if they spend a lot of time in the sun or play with lasers. Now I have to wear...

Maybe I should restate the question. This is for Wikipedia articles on lasers, including history of lasers. Are any non-DPSS 670nm laser pointers still being commercially produced and available to the consumer through ordinary retail channels? I don't mean DIY jobs, but something you can buy in...

Thanks for the feedback. You've convinced me. The clincher was the light bouncing around inside the diamond and reflecting off its facets. I've seen what an ordinary laser pointer does, and it's not what I need. Diffuse light is definitely the way to go. Even binned diodes are notorious for...

Thanks for the feedback. Besides wanting a low-power 670nm laser pointer, I'm also doing research for several Wikipedia articles (on lasers) that I am editing. In particular, the claim that 670nm is the most common wavelength of cheap laser pointers (which appears in some form in several...

5mW would be fine. :can:

Actually I do. It's an 8-point G VS2 with very good cut, polish, and symmetry, and no fluorescence. Diameter: 2.79 mm. Depth: 1.69 mm. Price: $38.88. In the world of diamonds, photography and lighting are key.

Thanks for all the feedback. Just doing a little more research, it looks as if 365nm laser diodes do exist, but only in the research lab. No indication of any in commercial production. The ones at 355 and 375 seem to cost thousands regardless of how few mW they produce. As for the industry...

The FastTech laser arrived two days ago. It is utterly amazing.

This thread raises the issue of Failure of Color Constancy. The image-processing centers of the brain try to keep the colors of objects we see constant even in greatly varying lighting conditions. A green car still looks green, even at sunset when most of the light from the sun is red. However...

Thanks for the heads up on FastTech. I did some research and found an amazing video review on YouTube by some guy named Andrew Willis. That convinced me to get that exact model (in the Aldary stylish white shell). Meanwhile, since this thread is partly about o-like, I went ahead and bought one...

Great review. I am currently in the market for some cheap lasers (405, 532, 640, 808; 50mW-200mW). O-like and Laserpointerpro seem to have the best prices, only Laserpointerpro seems to have an awful reputation, while O-like's is merely a bit spotty. From what I have read here, I am willing to...

I need it for evaluating diamonds for fluorescence. The standard reference wavelengths in the diamond industry are 254 nm and 365 nm. However, 254 nm is only used to determine what kind of diamond it is (type IIb, etc.) while the fluorescence measure that goes on the certificate is based on 365...