250mw red to white flashes.

[Kenom]

we've all commented how when a red laser is focused perfectly you get white light. Nobody really knows what causes it but the most popular argument being that your eyes become over saturated with light. Well, I was playing tonight and saw it even through my laser shades, so I figured I'd film it. Here it is.

http://s270.photobucket.com/albums/jj105/kenkassidy/?action=view&current=flashes.flv

 

[yobresal]

Love the vid. I just tried the same thing. I am clearly seeing some white light when I get the laser focussed all the way down. I bet you wish you had those goggles on you instead of the camera. That white dot is intense.

 

[Switch]

I get that too....Even get some purple-ish flashes when I burn some black rubber.Maybe the material is so overwhelmed with energy that it turns to plasma? :-/ Do you guys only get this with red?

 

[FireMyLaser]

Maybe when focused it makes allot of heat. Heat=IR which the camera can see as white?

 

[styropyro]

My 100mW 780nm laser does the exact same thing, it makes flashes of white light when you find the sweet spot.

 

[Benm]

It IS just heat, nothing special about it. When you focus 200 mW of light on a tiny spot on that cigarette, that part just heats up to the point of thermal emission. The goggles make this visible on camera, as the red light is blocked out for the most part and thus the blackbody radiation of the target becomes more visible.

I think you'd find it very difficult to reproduce this effect using for example a black anodized heatsink as the target - it just doest heat up enough.

The effect has nothing to do with 'overloading' your eyes, the inner workings of the eye are such that you will always see red as red, all the way up to the point where the intensity will damage your eyes. This is completely different from a camera, where it is quite usual to overload the sensor and make the dot look white with a red corona around it.

 

[Switch]

But this isn't just heat....It's white light! you can see it with your eyes , not only the camera.

This is completely different from a camera, where it is quite usual to overload the sensor and make the dot look white with a red corona around it.

Actually I kinda see my red dot on a white wall the same way with bare eyes.It kinda has a white or orange center....but maybe that's just the way really bright red looks like :-/

 

[toked323]

yea its not IR because the human eye can see it, it also meens its focused to burn like hell

 

[Kenom]

It IS just heat, nothing special about it. When you focus 200 mW of light on a tiny spot on that cigarette, that part just heats up to the point of thermal emission. The goggles make this visible on camera, as the red light is blocked out for the most part and thus the blackbody radiation of the target becomes more visible.

I think you'd find it very difficult to reproduce this effect using for example a black anodized heatsink as the target - it just doest heat up enough.

The effect has nothing to do with 'overloading' your eyes, the inner workings of the eye are such that you will always see red as red, all the way up to the point where the intensity will damage your eyes. This is completely different from a camera, where it is quite usual to overload the sensor and make the dot look white with a red corona around it.

Well, I don't know if I agree with the IR from heat explanation cause I can see it with my naked eye. however, I was UNABLE to produce the effect on a black heatsink as you suggested. so your explanation has merit. I believe that this is from intense heat from the laser that part I can believe and I certainly am not arguing with you not having the knowledge to form a hypothesis.

 

[FireMyLaser]

Yeah this is weird.
Well, when I was at my dads work, he tested a 25w, 1064mn laser burning some paper and wood. When it burned the wood was like a firework-fuse. The light is invisible, but i could clearly see that mysterius white light and the sparks flying from it.

 

[Switch]

I still think it's hot ionized matter due to a lot of energy in little time on a small spot.

 

[clwatkins10]

ya, ive noticed that too, its weird, ive always assumed that it was because there is so much red light that it appears white, kinda like how some stars seem white even though they might be a yellowish orange :-? just an idea...

 

[knimrod]

Benm is correct but didn't say the word..  The effect is "incandescence".

 

[Switch]

ya, ive noticed that too, its weird, ive always assumed that it was because there is so much red light that it appears white, kinda like how some stars seem white even though they might be a yellowish orange :-? just an idea...

That can't be right since it passes through goggles.

Benm is correct but didn't say the word.. The effect is "incandescence".

Are you sure? No plasma? :'(

 

[clwatkins10]

ya, the plasma thing makes more sense

 

[Schrecken_Licht]

I've not seen it with my 173mw red, but I have seen it with my CO2 laser. On certain materials (generally a focused beam) the target will glow white-hot like the filament of a clear 150 watt light bulb - almost too bright to look at comfortably (for CO2 lasers all you need are ordinary plastic safety goggles and while they fully block the CO2 wavelength they don't of course block visible light at all).