808nm - harmful or not?

I have done some experiments with a 1W 808nm LD. I did put a lens on it, an it burns the heck out of everything black. However, when I focus the 1W light directly to my skin, nothing happens. Did the same thing with red surfaces too - nothing happens. So my idea is that, even if the power is 1W, it is not that harmful as a 10mW green og 405nm. Green or 405nm actually burn skin already at a few mW, but a 1000mW 808nm did nothing at all.

So to my point: A green 5mW laser is much more harmful to your eyes than a red raser at the same optical power. The red colored retina in our eyes is absorbing the green colour much more efficient than red light are. This means that more heat is created, and more damage is created with a green color than a red color.

So be also very cautious about 405nm lasers. Even 1mW can damage your eyes, and we guys are playing with up to 300mW of this violet lasers!!

OK. Take care folks, and do not stare into your laser - even if you believe the power rating of less than 5mW is "safe" for all colors.

Br.

Vidar

Low-Q said:

I have done some experiments with a 1W 808nm LD. I did put a lens on it, an it burns the heck out of everything black. However, when I focus the 1W light directly to my skin, nothing happens. Did the same thing with red surfaces too - nothing happens. So my idea is that, even if the power is 1W, it is not that harmful as a 10mW green og 405nm. Green or 405nm actually burn skin already at a few mW, but a 1000mW 808nm did nothing at all.

So to my point: A green 5mW laser is much more harmful to your eyes than a red raser at the same optical power. The red colored retina in our eyes is absorbing the green colour much more efficient than red light are. This means that more heat is created, and more damage is created with a green color than a red color.

So be also very cautious about 405nm lasers. Even 1mW can damage your eyes, and we guys are playing with up to 300mW of this violet lasers!!

OK. Take care folks, and do not stare into your laser - even if you believe the power rating of less than 5mW is "safe" for all colors.

Br.

Vidar

Click to expand...

Power is power. No matter the wavelength. 1W of 532nm = 1W of 405nm

Now what has you concerned is the absorbance of IR on human skin. It is true, you can try that experiment if you own a high powered red pointer and a moderately powered bluray pointer.

If you focus 200mW of 650nm on your arm, you'll barely feel anything. You also won't see the dot as focused as it'd be on another surface like black cardboard. Now if you try with 100mW of 405nm then you will feel a burning sting. This is because your skin can absorb 405nm much better than 650nm. Extrapolating, same thing applies to UV and IR.


EDIT: You also have to take into account that shorter wavelength allows for focusing photons into a smaller area.

very very wrong. listen to this ^

Low-Q said:

I have done some experiments with a 1W 808nm LD. I did put a lens on it, an it burns the heck out of everything black. However, when I focus the 1W light directly to my skin, nothing happens. Did the same thing with red surfaces too - nothing happens. So my idea is that, even if the power is 1W, it is not that harmful as a 10mW green og 405nm. Green or 405nm actually burn skin already at a few mW, but a 1000mW 808nm did nothing at all.

So to my point: A green 5mW laser is much more harmful to your eyes than a red raser at the same optical power. The red colored retina in our eyes is absorbing the green colour much more efficient than red light are. This means that more heat is created, and more damage is created with a green color than a red color.

So be also very cautious about 405nm lasers. Even 1mW can damage your eyes, and we guys are playing with up to 300mW of this violet lasers!!

OK. Take care folks, and do not stare into your laser - even if you believe the power rating of less than 5mW is "safe" for all colors.

Br.

Vidar

Click to expand...

You can't base eye damage on the same factors as skin damage. The retina is sensitive to all visible wavelengths, but the sensitivity does vary depending on wavelength. How much a laser burns skin is irrelevant to a laser's capability to ruin the receptor cells on the retina's surface.

I do agree with you that 405nm light is several times more dangerous than near IR, but 808nm IS DANGEROUS. This danger is amplified by the fact that it is invisible. The "eye-safe" region of the IR spectrum doesn't begin until you reach ~2000nm, so any wavelength shorter than this is potentially a serious eye hazard. Just because it doesn't easily burn your skin doesn't mean that it won't hurt your eyes. Your eyes are much more sensitive to light of all wavelengths than your skin, and the lens of the eye tends to focus incoming energy on the retina.

No offense, but please don't base your ideas about laser safety on haphazard personal experimentation and then post it here as possible fact.. I know you had good intentions, but there is much scientific documentation which covers laser safety already which has been compiled by scientists and optoelectronics professionals who have the knowledge and facilities to do proper research.

If you or anyone ever have questions about laser safety, the answers can be found here: Rockwell Laser Industries: Laser Safety Training, Products and Consulting - laser safety glasses and goggles, laser safety standards, Barriers and Curtains, Warning Signs and laser safety labels

I do not say that a IR light is not damaging anything, but that a red surface is less damaged by red or 808nm light than green og shorter wavelengths. I also did warn you guys about the quite harmful 405nm as the wavelength contains more energy - and that you should not trust that a 1mW 405nm laser does not cause eye-damage. Even an unfocused 100mW violet laser can cause skin burn. It is not only the possible smaller focused dot that is the main cause of damage - but it is an "advantage".

I do agree that posting personal experiments as facts, is not very wise. However I only questioned if a 808nm light damages retina as much as a shorter wavelength and assumed I was right about my own ideas - I have never tried to look into a 1W 808nm laser with optics. How many serious scientists have tried to see how much an 808nm laser at 1W is damaging their eyes, and posted the results in the public anyway? Maby I find some answers on the subject in your links. Thanks for the links btw

I'll also google on the subject.

Br.

Vidar

1W 808 nm laser is a class 4 laser. it is harmful. it will burn the skin and eye and it is invisible so it is more danger than the visible light in some point.
The green or violet laser will cause fires faster than the 808 nm laser. it is also transmit more to human body so it is not like green laser which is absorption at the surface area. so it is not feel hurt in a short time like green laser.