3W 445 + 1W 532=white WHY?

[blrock]

This past weekend I combined my blue laser and fine tuned my "laser system". To my astonishment the beam appeared pure white. I never even added any of my 635nm red.

 

[danefex]

Do you know how amazing a picture of that would be?

 

[blrock]

Do you know how amazing a picture of that would be?

I'll take some pictures this weekend and post them....

 

[danefex]

Sweet! Pictures of tight white beams always have impressed m..... ahhhh that doesn't sound right now does it?

 

[Flaminpyro]

Yep lets see it op:

 

[anselm]

I'd say what you got from 445nm plus 532nm is CYAN.
In order to get WHITE, you'd need some red (650 or 635nm) in there as well.

Maybe it looked white to you because it was simply so very bright.

Want to see pictures too, even though they are hard to make and often betray the real colors you see in person.

 

[Lazy Laser]

Can't wait for pics op:

 

[rhd]

Anecdotally, whenever I've showed Blue + Green to non laser (or non-sciency) people, the comment about their combined dots (low-tech, just aiming the dots together) is always "ohhhhh, look, white!"

Don't forget, 532nm is slightly to the *right* of the tip of the CIE curve "hump". Wow this answer has poor scientific terminology ;p But if you were to draw a straight line between 532 and 445 of the the following curve, it definitely takes you pretty close the the inner "white" territory, as opposed to hugging the curve itself:

 

[Cyparagon]

Your eyes have an automatic white balance. If you sit in a green light for long enough, and it starts to appear white. You're not seeing white. Compare it with a light bulb and you'll see what I mean.

 

[jmgallego]

Are looking at the combined spot without safety glasses?? If you are, your eyes are just being oversaturated and protecting themselves by giving you the impression that you are seeing "white". You are looking at laser with a total of 4W.

Be careful, you may be damaging your eyes.

Take care of them.

This past weekend I combined my blue laser and fine tuned my "laser system". To my astonishment the beam appeared pure white. I never even added any of my 635nm red.

 

[joeyss]

It could also be due to florescence effect of both wavelengths , particularly 445nm.

 

[Benm]

Fluorescense does not affect the color of the beam though, just that of the dot. Its like shining a bluray laser onto white paper - you get a purple beam and a brilliant bluish-white spot.

Color adaptation in the eye is a feasible explanation though, especially if you were working with little ambient light. Your eyes only get the light from the lasers and make a color construction based on that information. There would be green and blue for the separate beams, but combined they could look white.

As similar thing happens when you spend a long period of time under those orange sodium lights: The world appears black and white, while the amount of light is great enough to allow color vision... just because its monochromatic your eyes will assume its white for you.

 

[blrock]

First of all apologies to everyone...You were all right. I think hours of alignment last weekend made me see white. I did wear googles but I carelessly took it off at times.

I used some smoke and took a few pictures for the first time. My laser system is almost complete...after so many months of building and alignment complications. Just have to drill new holes for the galvos as I'm a few mm off my x-axis. The cyan beam is SO bright...

PS: the fans from the A130/A140 projector works well to keep the 445 heatsink cool. They high power fans...

 

[danefex]

Now that is amazing! I see what you mean in the 3rd pic about how close it does comes to solid white too, or so it would seem with the intense brightness.... :beer:

 

[blrock]

Now that is amazing! I see what you mean in the 3rd pic about how close it does comes to solid white too, or so it would seem with the intense brightness.... :beer:

Yes it does seem white..
Best part is that I change my palette on the software to get rid of the very common 532 green. I added some blue to get what I think is very close to the Argon 514 green. My favourite laser colour. I've spend the past half hour staring at the green beam.

The picture does not quite do justice for the actual colour...but it's not far off..

 

[BennyF]

what is that stray green beam going to the left in the 3rd and 4th picture?