A strange phenomenon

[opr]

A strange phenomenon I don’t understand:
I have a green laser. To my understanding, it produces pure green 523nm light.
There is a reddish plastic that while pointing the laser to it, converts the Green dot to be Yellow.
I can’t understand where this yellow color comes from. I would expect Green to stay Green. Very strange.

 

[Alessandros]

Color Subtraction

Yellow light is a combination of red and green light.

It happens because the red plastic is reflecting red light, and then you add green, so that makes yellow.

 

[opr]

I would agree if there were any source of Red light. But there is no Red light to reflect. I did the experiment in the dark. The only source of light was the Green laser.

Other Red stuff I point on, just reflect the Green as is in some kind of reduced power.

Can it be that a piece of plastic changes the frequency of the light?

 

[Alessandros]

In that case, it could just be the perfect shade of red to allow it to fluoresce, in a sense.
I point my green laser at orange plastic, and it lights up neon orange, so it could be the same thing.
Sorry I couldn't help more, my knowledge of light ends here.

 

[RA_pierce]

It's fluorescence.
The green light excites the atoms in the dye of the plastic. When the electrons relax from their excited state they give up their energy in the form of light of a shorter wavelength.
In this case, yellow.

The yellow/orange light does not come from the laser. It comes from the plastic.

Try pink hi-lighter juice mixed with some water, olive oil, colored dish soap... all kinds of things fluoresce.

 

[daawood123]

wow, so you could make a yellow laser by sticking that red plastic in front of it?!

 

[Alessandros]

I don't think so, because it's the actual plastic that fluoresces, not the laser beam. You could make a yellow dot appear on the plastic, but after that, the laser's colour would be uneffected.

 

[daawood123]

ahh so the dot is only yellow on the plastic. OP said it converts the dot to yellow, so i thought it turns the laser yellow.
aw well

 

[Alessandros]

ahh so the dot is only yellow on the plastic. OP said it converts the dot to yellow, so i thought it turns the laser yellow.
aw well

If only :cryyy:

On the other hand, it would be yellow for all demonstrative purposes if you used it for a spirograph.

 

[RA_pierce]

If you shine the laser through a glass jar of hi-lighter fluid mixed with some water, the green beam will enter, appear to change to yellow, then exit green again.

It's not the laser beam that changes. It just helps the dye to emit light of a different wavelength.

Try it.

 

[opr]

Thanks. that explains it.