488+638= white?

[Benm]

Colour is all about perception indeed.

But if you get a right mix of colors that bisect white in the gamut, the beam will look white to most people. It may look when illuminating things, color rendition from 2 monochromatic wavelengths will be very bad, but the beam and dot will pass as white.

RGB systems have the same limitations though: they cannot produce a pure cyan, yellow or magenta.

If you just take a red and a green laser an vary the ratio of power between them, you can produce any color like orange, yellow, lime etc. Still this is different from a monochromatic source producing that same colour, and also from any other system that, on average, outputs that colour.,

 

[micheal rosen]

Anyone test if transmit/reflect blue+green reflect/transmit red will transmit/reflect cyan wavelengths efficiently? Hopefully you guys know what I mean. I actually don't know If there are reflect blue+green dichros.

 

[Encap]

Anyone test if transmit/reflect blue+green reflect/transmit red will transmit/reflect cyan wavelengths efficiently? Hopefully you guys know what I mean. I actually don't know If there are reflect blue+green dichros.

Not quite aure what you want to do but Edmond Optic has Cyan and other secondary color Dichroic filters
https://www.edmundoptics.com/optics/optical-filters/color-dichroic-filters/Additive-and-Subtractive-Dichroic-Color-Filters/

Mirrors and other Dichroic items here: https://www.edmundoptics.com/optics/optical-filters/color-dichroic-filters/

What lasers do you have and what do you want to accomplish with them --exactly/specifically?

45° Dichroic Filter
Forty-five degree dichroic mirrors and filters guide light by selectively transmitting and reflecting different wavelengths – commonly used to combine light from multiple LEDs or lasers into a common light path, or in reverse separating white light or fluorescence excitation and emission bands into discrete components. Since dichroic filters are angle-dependent, the standard versions of 45° dichroic filters are designed to operate at a 45 degree angle of incidence; custom angles and illumination sources are available on request.

 

[micheal rosen]

Not quite aure what you want to do but Edmond Optic has Cyan and other secondary color Dichroic filters
https://www.edmundoptics.com/optics/optical-filters/color-dichroic-filters/Additive-and-Subtractive-Dichroic-Color-Filters/

Mirrors and other Dichroic items here: https://www.edmundoptics.com/optics/optical-filters/color-dichroic-filters/

What lasers do you have and what do you want to accomplish with them --exactly/specifically?

45° Dichroic Filter
Forty-five degree dichroic mirrors and filters guide light by selectively transmitting and reflecting different wavelengths – commonly used to combine light from multiple LEDs or lasers into a common light path, or in reverse separating white light or fluorescence excitation and emission bands into discrete components. Since dichroic filters are angle-dependent, the standard versions of 45° dichroic filters are designed to operate at a 45 degree angle of incidence; custom angles and illumination sources are available on request.

I'm just curious if those cheap ebay dichros would work with ~488nm and 638nm lasers so you could make a cheap white laser with them. Im not really planning anything yere yet, sotheres no real directon to this thread it's more just building the knowledge base for future reference. I think I will do a combined build eventually.

 

[Encap]

I'm just curious if those cheap ebay dichros would work with ~488nm and 638nm lasers so you could make a cheap white laser with them. Im not really planning anything yere yet, sotheres no real directon to this thread it's more just building the knowledge base for future reference. I think I will do a combined build eventually.

Doubt anyone has the answer about cheap eBay dichros and 488nm + 638nm lasers to make the illusion of a/a fake white laser--is an eccentric thing to do.
A bunch of mixed cheap stuff on ebay not designed for your purpose is going to be a poor quality imaginary white illusion probably. The only way to really know is to buy them and try them ---see wht results you can get with enough fine tuning and tweaking.
Ask yourself why nobody does white simulation/illusion lasers this way?

Where do you expect to buy a cheap 488nm diode? Are they not $500 to $1000 for a PL5488nm diode?

Those cheap dichro mirrors at Edmund cost $75 to $100 each

How are you going to balance the output to get as close to white as possible?

What output overall do you expect or need to have?

If you don't have a real need or purpose in doing it that way, probably you a much better off if you want to make a cheap imaginary white laser get your feet wet with the limited illusion of white laser with one of the $49 RGB modules at laserlands https://www.ebay.com/itm/RGB-300mW-White-Laser-Module-Red-650nm-200MW-Green-532nm-50mW-Blue-450nm-80mW/372132880223?hash=item56a4d91f5f:g:rRkAAOSwDkVaCRMD

If cheap does not matter and you just want to play and experiment a bit with 488nm plis 638nm, then expect to spend time and money.

Email Edmonds help people and ask them what to get to do what you want to do---is a good bet they will give you a good answer--- see: https://www.edmundoptics.com/contact-support/help-center/

 

[Benm]

I think the main reason people don't use 2-color mixes to get white light is that is the only thing you can do with them - apart from producing off-white light either to the cyan or pink which are not that attractive.

With 3 color RGB mixing you get a decently usable color space which is much nicer for laser shows and such, and it's not more expensive either. It's more difficult to adjust beam alignment, but that's the only real downside.

So yeah, if you -just- want a beam that looks white you can do it with two wavelengths as long as their position on the gamut chart intersects pure white.

As far as a dichro would go: I doubt you'll find any specific for these wavelengths, but one designed to combine 635 with 532 or 635 with 450-ish would probably work with acceptable losses.

That RGB module on ebay looks temptingly cheap - i wonder if it meets power spec by a long shot and how good the aligment is, but if they are good it's the cheapest solution i've ever seen at this (quite low) power level.