445nm to White or yellow

[masterpj]

Hi everyone,

I'd thought I'd kick of another conversation.
Recently I got some special "filters" that I think use fluorescence to convert blue lasers into white or yellow.

Intrigued I reached out and bought the components as parts.
I power both units and indeed out comes a very wide spread white and yellow (see pics below)

I noticed a lack of speckle.. first weird part of it.

However I persued and teared down the white unit:
What I got was this:

A black removable plastic cap contained the entire assembly that converts the 445nm (1watt blue diode outputting 943mw ) to the "white".

I held it in front of a 445nm laser to try and it worked great.
445nm blue laser output once black assembly is removed:


The spread on it is enormous so I tried a focusing lens and while I could get it in focus I would get a fairly large spot.. no speckle but all in white with a little bit of color separation if you'd tilt the lens.
A larger lens was included which I could get this from if I moved it away a bit from the assembly:
.
I tried smaller lenses assemblies like the ones used in aixis laser housings.. sadly that didn't improve much.
Here are pictures of the small black assembly:




Either the emitter turns huge or this light has lost it's coherency upon the conversion. Any thoughts?

[james]

Yes. The white light cannot possibly be coherent or polarized so it's no longer laser light.

[masterpj]

Ah damn. I thought it was possible but the trade of was that there was a short life span.
I guess the same goes for the yellow

[masterpj]

checked out the yellow. Assembly is identical.. the only difference is a filter on top.. probably is some kind of dichroic that just keeps reflecting the remaining light back and letting through only the yellow portion.
Was hoping there was maybe a way to get something out of it but that's a shame!

[kecked]

It works same as white led. 445 causes yellow fluorescence. That mixed with the blue is white to your eye. Add a blue filter and you only see the yellow. Sorry no laser action there.