4 ms·

800 nm (NIR) does present hazards. Most people can't se it until the intensity is very high, so you blink reflex doesn't protect you. Having said that, it is p

800 nm (NIR) does present hazards. Most people can't se it until the intensity is very high, so you blink reflex doesn't protect you. Having said that, it is probably highly divergent out of the fiber (depends on type). There's no risk beyond a few cm. Don't stick the fiber it up against your eye though. To answer someone below its unlikely you could get burned except right at the fiber tip. You can stick your hand in a 1.5W beam as long as it isn't tightly focused.

lightedman 3y ago
"it is probably highly divergent out of the fiber" Those of us in the styropyro discord have found that to almost never be the case. WEAR EYE PROTECTION AT ALL TIMES.
- avsteele 3y ago
  What types of fibers are you talking about?
  - lightedman 3y ago
    Single-mode, multi-mode, etc. All fibers. Let's use my LASER marker at work as an example. Divergence in that fiber happens AFTER two things happen - first the photons need to leave the fiber,then they have to cross-over their 'hip' (where the collimated beam is tightest) THEN they diverge. That's how fiber LASER markers work. I'm the operator of them where I work (I do everything outside of SMT - x-rays, LASER marking, high-voltage testing, etc.) Every LASER coming out of that fiber hits focal point about 2 feet past the fiber, where it begins to diverge. Do not trust a LASER coming out of a fiber to be unfocused or not have enough power density to blind you. Period.
    - avsteele 3y ago
      That's fine safety guidance but on the facts this is not correct. For single and multimode fibers if it has a smaller focal spot some distance the fiber than at its tip you are talking about an assembly that includes the fiber plus an optic. This is unambiguously true for single mode fibers. Multi mode one will diverge less I could see there being some exception for a strange fiber which has a multi-emitter output, was nanostructured, tapered, etc..
      - lightedman 3y ago
        "For single and multimode fibers if it has a smaller focal spot some distance the fiber than at its tip you are talking about an assembly that includes the fiber plus an optic." A properly-shaped and polished fiber tip is already the optic. That's literally how it's fed into the galvo in a fiber-marking LASER. I'm also responsible for the maintenance on all equipment in the facility so I've had those machines apart more than once.
rubidium 3y ago
Agreed. A 40W 1550nm laser I used in grad school would burn post it notes readily and slowly burn black painted objects. It gave me a little burn once too (Was like touching a hot stove). 1.5W focused to 100 um would be a zinger, but at 4 mm would be not super dangerous thermally. The main risk is you couldn’t see it so no blink reflex to help from even specular reflections. Regardless, it would be reckless to expose this to people without eye protection.
- weberer 3y ago
  I think your laser was 40mW. A 40W laser can engrave steel.
  - NietzscheanNull 3y ago
    Judging by the fact that they mentioned being in grad school at the time and that the laser was infrared, I imagine engraving steel isn't too far off from what they were using it for.
    - BenjiWiebe 3y ago
      But they mentioned it would slowly burn black painted objects.
      - gorlilla 3y ago
        It's all about absorption spectrum. 40W at 10600nm will burn clean through a few mm of wood but could only maybe lightly etch brass and be utterly useless on aluminum. 40W of energy is being delivered, what happens to the thing it's being delivered to is entirely dependent on absorptive potential.
  - xxs 3y ago
    Agree on the 3 orders of magnitude difference. 40W soldering iron will inflate post-it notes, 40W laser steel/stone engraving/cutting area.
  - 3y ago
no_wizard 3y ago
When you say most people, are there in fact people that can see this at low intensity?
- NavinF 3y ago
  Most (all?) IR lasers leak visible light too. Look into any 1310nm SFP module and you'll see red light even though 1310nm is well outside the visible range. And no, this won't burn your eyes out. Despite what the clipboard warriors claim, a laser that's designed to couple to fiber will not magically focus itself at the exact distance where your eyes are located. Instead the beam will diverge as if the 1mW laser was a 1mW LED.
- avsteele 3y ago
  I can see 780 nm (rubidium laser cooling light) specularly reflected from an index card at maybe 100 mW, if memory serves.

lightedman 3y ago

"it is probably highly divergent out of the fiber" Those of us in the styropyro discord have found that to almost never be the case. WEAR EYE PROTECTION AT ALL TIMES.

avsteele 3y ago
What types of fibers are you talking about?
- lightedman 3y ago
  Single-mode, multi-mode, etc. All fibers. Let's use my LASER marker at work as an example. Divergence in that fiber happens AFTER two things happen - first the photons need to leave the fiber,then they have to cross-over their 'hip' (where the collimated beam is tightest) THEN they diverge. That's how fiber LASER markers work. I'm the operator of them where I work (I do everything outside of SMT - x-rays, LASER marking, high-voltage testing, etc.) Every LASER coming out of that fiber hits focal point about 2 feet past the fiber, where it begins to diverge. Do not trust a LASER coming out of a fiber to be unfocused or not have enough power density to blind you. Period.
  - avsteele 3y ago
    That's fine safety guidance but on the facts this is not correct. For single and multimode fibers if it has a smaller focal spot some distance the fiber than at its tip you are talking about an assembly that includes the fiber plus an optic. This is unambiguously true for single mode fibers. Multi mode one will diverge less I could see there being some exception for a strange fiber which has a multi-emitter output, was nanostructured, tapered, etc..
    - lightedman 3y ago
      "For single and multimode fibers if it has a smaller focal spot some distance the fiber than at its tip you are talking about an assembly that includes the fiber plus an optic." A properly-shaped and polished fiber tip is already the optic. That's literally how it's fed into the galvo in a fiber-marking LASER. I'm also responsible for the maintenance on all equipment in the facility so I've had those machines apart more than once.

rubidium 3y ago

Agreed. A 40W 1550nm laser I used in grad school would burn post it notes readily and slowly burn black painted objects. It gave me a little burn once too (Was like touching a hot stove). 1.5W focused to 100 um would be a zinger, but at 4 mm would be not super dangerous thermally. The main risk is you couldn’t see it so no blink reflex to help from even specular reflections. Regardless, it would be reckless to expose this to people without eye protection.

weberer 3y ago
I think your laser was 40mW. A 40W laser can engrave steel.
- NietzscheanNull 3y ago
  Judging by the fact that they mentioned being in grad school at the time and that the laser was infrared, I imagine engraving steel isn't too far off from what they were using it for.
  - BenjiWiebe 3y ago
    But they mentioned it would slowly burn black painted objects.
    - gorlilla 3y ago
      It's all about absorption spectrum. 40W at 10600nm will burn clean through a few mm of wood but could only maybe lightly etch brass and be utterly useless on aluminum. 40W of energy is being delivered, what happens to the thing it's being delivered to is entirely dependent on absorptive potential.
- xxs 3y ago
  Agree on the 3 orders of magnitude difference. 40W soldering iron will inflate post-it notes, 40W laser steel/stone engraving/cutting area.
- 3y ago

no_wizard 3y ago

When you say most people, are there in fact people that can see this at low intensity?

NavinF 3y ago
Most (all?) IR lasers leak visible light too. Look into any 1310nm SFP module and you'll see red light even though 1310nm is well outside the visible range. And no, this won't burn your eyes out. Despite what the clipboard warriors claim, a laser that's designed to couple to fiber will not magically focus itself at the exact distance where your eyes are located. Instead the beam will diverge as if the 1mW laser was a 1mW LED.
avsteele 3y ago
I can see 780 nm (rubidium laser cooling light) specularly reflected from an index card at maybe 100 mW, if memory serves.