Laser Reflection

[Invisible]

Greetings,
If I irradiate a white surface that been coated with a phosphor that excites at 980nm and emits in the visible range (such as a test card) is there any chance that the reflected image can damage my eyes?

 

[KrowBar]

Sure. That will mostly depend on the incident irradiance, the divergence angle, and the reflective properties of the surface+coating. Likely, the coating is designed to be highly absorbent, so only a small fraction of the incident beam would be reflected (and diffusely at that), but given a high enough incident power, and if you are close enough to the reflecting surface, you could still cause damage. What is less likely is that the emitted visible light would be damaging, since phosphorescent time scales are much longer, so they release absorbed energy at a lower power level. And if your irradiating source is in the IR range, you may see the dim visible emission and feel safe while still cooking something you don't want too. When considering safety, always assume that something unexpected might happen, like something else more reflective momentarily moving in front of your beam (I've more than once been surprised at the bright flashes when mosquitoes and such fly through a skyward beam at night) so take appropriate cautions.

 

[paul1598419]

I've used these IR cards before and they are okay for detecting the IR and are not made to be reflective, or specular. However, I use an IR camera to detect and collimate IR lasers. You might think about this as an alternative.