The yellow beam

[RickSCV]

I saw a few weeks or a month back in some post that I cant find anymore that someone was able to make a yellow beam from combining 600mw of red and 100mw of green.

I want to try this!

However Im not exactly all that familar yet with external optics so I have no clue how he was able to pull this off. Anyone have any ideas? :thinking:

 

[nanoWatt]

I am no expert, but I know that dye lasers can get yellow, and are tunable for the most part. They can be messy though, and some of the liquid dyes are toxic so need care. But I saw a yellow laser at Rice University that was a dye, and it was very beautiful.

 

[jrv]

There are 593nm lasers that are yellow. They're DPSS and not brighter than than 473nm blue. Laserglow sells the Vega at http://www.laserglow.com/index.php?vega which is between 2mW and 10mW depending on how lucky you get with the crystals. Their Rigel at http://www.laserglow.com/index.php?rigel is a point at <= 2mW.

Neither has a beam bright enough to be seen unless you add some smoke to the air.

 

[nanoWatt]

You may want to research dye lasers then. They can have a bright enough yellow to see in the daylight. However, they are more complicated since they use a UV pumping source from what I remember. But if I'm not mistaken you can get around a Watt of yellow this way.

Also, dyes get "eaten up" so to speak. They have a certain useful life and need to be replaced every so often. The dye laser also is not very portable if that's what you are looking for. Most dye lasers have flowing dye, which helps cool and minimize bleaching.

You could read Sam's FAQ if you're interested: http://www.repairfaq.org/sam/lasercdy.htm
There is a posting there about using yellow fluroescent markers as dye.

 

[allthatwhichis]

Hey Rick, try over at photonlexicon for advice on this. I can give you a quick overview but the experts will have a better explination.

You take dichroic filters to mix your beams. You purchase them based on the wavelength or color you want to transmit and reflect. Say you have your 100mW green and 600mW red. You will want to decide which you want to reflect and transmit. I think reflectivity will lose less, transmit will lose more. In my RGB projector I have it backwards and am loosing more red than green and need to replace my filter and swap laser positions. I suggest getting a dichro that transmits green and reflects red, although, 6:1 my give you a little too much red in your yellow depending on the wavelength. Is your red 635, 650, 660, or 671? 100mW of 532 should mix fairly well with 600mW of 660 or 671 but 635 or 650 may give you a more orangey yellow as they are perceived brighter by our eyes. I would get a reflect red, transmit green, as your green is the cheaper per mW. This one should work. You will end up with approx 80 to 90mW of green and 550mW of red from 100/600 given the transmit and reflectivity loss.

Once you have the dichro, get your lasers at the same height and point the transmited color through the dichro and point the other at the reflective side of the filter at a 45 degree angle where the dots of each laser are at the same spot on the filter. One will go through the filter and one will bounce off of it and should be going the same way and combigned it the alignment is good. Your dichros "should" be in a mount that you can adjust in the x/y and sometimes z to align the beams into one beam.

 

[RickSCV]

Oh thanks Allthat! You are all that! lol. I really appreciate your help as it was EXACTLY what I was looking for. I also appreciate everyone else who posted.
This is going to be my science project for the begining of the year I havent gotten the red laser diodes yet so now I know what to look for. Although orange does sound slightly appealing, but hey thats another project a few months down the line. :twothumbs

 

[ixfd64]

The problem about combining red and green is that it does not yield a "true" yellow beam. Actual yellow DPSS lasers are very expensive because of their very complicated process.

 

[nanoWatt]

I wonder how expensive those dyes in a solid host would be. I know yellow neon signs use some kind of phosphor to get the yellow glow.

The problem about combining red and green is that it does not yield a "true" yellow beam. Actual yellow DPSS lasers are very expensive because of their very complicated process.