Single Mode RGB Diode Balance

[swamidog]

i don't really feel like i have a power balance issue with a single 50mW green and a 120mW red. i tweeked the currents slightly to get a nice balanced white at full power and it's surprisingly bright.

So, two 50mW greens and the 120mW red and blue should be pretty good. Now what lenses? Doc, the aspheric is to compensate for the very short FL. The multimode give complex and asymmetrical beams and a radially symmetric lens of simple spherical or aspherical design is always going to be a compromise. My guess is the best lens for the multimodes will be the best for the single modes, but to avoid a lot of telescoping up or down to fit say the 3mm aperture scanners what lens will be the best match for diameter/ divergence and cost?

[The_Doctor]

My guess is the best lens for the multimodes will be the best for the single modes...

Good enough for me. That's always been my thought too. Re focal length and diameter matching, I aim to go with FL about 4mm because that's usually worked well without imposing specific demands. I later took to 3.3ml FL acrylic aspheres, but one reason I turned to glass lenses recently was the annoying temperature dependence of acrylic mounted in metal. We could call the ability to fine tune focus with temperature control a 'feature', in the Microsoft sense of the term, but in the long run it loses its appeal. From what I could see in my photo of DTR's LFL lens it looks like there may be some variation in focal length depending on where the light arrives, i.e. not exactly one singular point of focus for some inversely fed parallel beam such as I used to get the imaged FL. In turn that looks like it might be more forgiving, more allowing of compromises with the astigmatism of a diode. Whether that's true, and what it may mean if it is, I don't know yet, but my next stage will be to fit a diode and fire it up, so not long now...

[planters]

Swammidog,

Then if it is close, I would want to double up on each diode with a PBS and make the same adjustments. So now it is the lenses and drivers. It would be nice if the drivers could handle the 24V of 1/2 of the scanner's power supply to allow a single PSU (24V +24V pair)for the whole thing.

[logsquared]

I have a unique solution for the single modes. I posted about it here: http://www.photonlexicon.com/forums/...313#post275313

I used the optima 4mm lenses. With careful alignment two sets could be knifed like "ll" and still fit on 3mm mirrors.

[loopee]

and the drivers I am familiar with are from Dr Lava, Wavelength Electronics and alas Badpip (defunct?)

and don't forget Dave has drivers http://www.photonlexicon.com/forums/...t=drivers+dave

[planters]

and don't forget Dave has drivers

Actually, I did and these look good. I will PM him about the comment he made about higher drive voltage. 24V will be easy in any projector with a scanner.

I have a unique solution for the single modes.

I like your module. I would use two of these side by side and one with its diodes rotated 90 degrees and prism directed to a PBS in front of each diode in the other module would double the power and permit your diode movement to either align the spots or fine tune collimation lens centration. Did you use the Optima 4mm for all the diodes? I have a lot of these.

[absolom7691]

Eric, with my SM RGB, I used the acrylic lenses to start with and found that the green needed some extra help. I ended up keeping the acrylics on my red and blue and bought a G2 for the green. I am also about 10mA over the spec sheet max on the green. With that, the balance is pretty decent.



Swami, did you get a chance to try out those dichros you were talking about?

[swamidog]

i have not tried those ebay dichros.. i have been so swamped with work and life for the last couple of weeks, lasers have had to take a back burner.

Eric, with my SM RGB, I used the acrylic lenses to start with and found that the green needed some extra help. I ended up keeping the acrylics on my red and blue and bought a G2 for the green. I am also about 10mA over the spec sheet max on the green. With that, the balance is pretty decent.



Swami, did you get a chance to try out those dichros you were talking about?

[absolom7691]

i have been so swamped with work and life for the last couple of weeks, lasers have had to take a back burner.

Hopefully it is a "blessed with work" kind of busy. Looking forward to many more of your abstracts when you're back at it again!

[swamidog]

i do have a new show in the works...

Hopefully it is a "blessed with work" kind of busy. Looking forward to many more of your abstracts when you're back at it again!