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Safety concern involving 650nm laser

tomtom9876

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Jan 19, 2020
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Right now, I'm building a 650nm laser, but I haven't tested it yet. Before I do, I want to make sure I buy the proper equipment. I've heard that some lasers also emit infrared light and can even damage your eyes if you're not wearing the properly rated glasses. So, do 650nm laser diodes emit infrared light?
 



Taylor21990

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No, they don't. The lasers that do are the "dpss" green 532nm. They emit infrared because they use an 808nm infrared laser diode which is shown into some crystals and emits a green light. They often times don't put in a IR filter in those cheap green lasers.
 

tomtom9876

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No, they don't. The lasers that do are the "dpss" green 532nm. They emit infrared because they use an 808nm infrared laser diode which is shown into some crystals and emits a green light. They often times don't put in a IR filter in those cheap green lasers.
So the only time I should be generally worried about infrared is when I'm using green 532nm?
 

paul1598419

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No. Any DPSS laser can emit IR. But, the amount is usually negligible compared to the amount of visible light. Also, the 532nm DPSS lasers don't emit 808nm IR. Tt is converted to 1064nm by Neodymium YAG or YVO4. That is frequency doubled to 532nm by KTP or other nonlinear crystals.
 

tomtom9876

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No. Any DPSS laser can emit IR. But, the amount is usually negligible compared to the amount of visible light. Also, the 532nm DPSS lasers don't emit 808nm IR. Tt is converted to 1064nm by Neodymium YAG or YVO4. That is frequency doubled to 532nm by KTP or other nonlinear crystals.
Is it really that negligible? I've heard that laser diodes without IR filters emit TONS of infrared light.
 

paul1598419

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You have heard wrong. Even the small fraction of IR content is following the same path as the visible beam until it diverges. That divergence makes it completely eye safe. It becomes a cone around the visible beam and only a fraction of its power could ever reach someone's eye. You should be far more concerned about the visible beam. If that is over 5 mW it can cause eye damage. The greater the power the greater the damage. Get some rated goggles.
 




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