Questions About TTL/Analog Modules and Creating an RGB Laser

Hello! Glad to finally be a part of this forum.

I am an avid DIY electronics enthusiast and the next project I want to create is an RGB laserharp. Last year I purchased plans online and built a laserharp around a 500mW 650nm (Red) analog laser module. I was happy with what I made, but I am more interested in designing something completely on my own.

This is going to be a long project, but I am comfortable figuring out the electronics side of things. My concern is with the "expensive" part-- the lasers.

Specifically, I was wondering how I should go about picking the laser modules? As in power ratios for the colors. I would use the red one mentioned above, and I was thinking I could go with a 250mW green module and then a 500mW blue module. Further, am I even right in thinking that it will be possible to use optics to combine the beams to get the desired RGB effect? My thought process is that by carefully combining separate, "nicer" modules I will be able to achieve a better color effect than with some sketch ebay "white laser" module or the like. I mean it probably won't look like the output of a $1000+ projector, but my goal is to just create a laserharp that can have various colors and animations.

given any thought to how the laser beams will be combined? Are you talking about having the beams in parallel, separated by a few mm? Or are you talking about getting the beams all traveling in the same volume of space, which would result in the beam really having the color of the combined light?

For option #2, the only way that I've seen it done was to use dichroic mirrors.
https://www.rp-photonics.com/dichroic_mirrors.html

This is probably going to require that you scavenge the dichroic mirrors out of a TV projector, assuming that they use these mirrors.

It's also going to require some mechanical skill to get the three beams aligned too. Not a trivial task.

I have to admit that I'm curious as to why 500mW lasers are needed. How far is the light traveling, and how sensitive is the receiver circuit? Seems like a significant safety risk to use such powerful lasers.

Use Analog type for better colors,smooth lines,Dichroic filters are used to combine RGB.you can get dicro filters from lighting rental stores.

When the beam is moving the observed images brightness is lowered,compared to just a static beam

Ah I never knew that about Analog vs. TTL. Thanks! And yeah, it won't be easy but I think it can be done via trial and error.

What about the power ratios? Does that matter? I have seen online that most people get by with a lower power green module (sometimes as low as 100mW, usually 250mW). I'm worried that the red and blue being drowned out by the green laser. If it helps, I plan on designing the harp with 9 beams. It will probably be adjustable, but 9 beams works/looks best in my opinion.

Making your 3 colors adjustable is almost a must. Red will be the least perceived color and green the most, so much higher red and blue vs. green. Making them fine tunable will allow you to tweak them brightness wise.

With the analog you will be able to control the power output on each channel,Yep Red you want to go big.