Not perfect as done quick, but here is a few of your images in yellow for you Paul.
Nice laser you have there.
Nice job CurtisOliver---more than adequate given all the differences in computer screens, graphics programs and drivers and setting of same.
These links may describe what's going on. See post 330.
Good links Steve001---they give good explanation of a 561nm/562nm DPSS process
Steve's links for those interested repeated are:
https://www.osapublishing.org/josab/abstract.cfm?uri=josab-30-1-95
https://patents.google.com/patent/WO2002021646A1/en
Why... Not sure. But it looks like at least two companies got lucky and found an easy coating that makes a somewhat difficult DPSS process cheap and easy to produce.
Lucky? I don't understand what you mean/are saying.
What two manufacturers are you meaning?
Who is the second manufacturer?
So far there is only one manufacturer making low cost/$30 574nm laser modules Shenzhen Optlaser that has been posted on LPF. At least that I have seen.
Do you mean "two companies" including retail reselling vendors that sell one piece at a time? Resellers, don't manufacture anything other than smoke and mirrors + high prices for lower cost products they purchase from a manufacturing entity and they don't find, come up with, or apply novel coatings to laser crystals--no?
Though this message likely will never be seen by the person who figured this out, thank you. I’ve searched for yellow for a decade. You’ve made a dream come true.
Do you mean low retail cost yellow?
Yellow has been around for a while now many companies have made them and make them on demand. THe problem has been mostly little or no demand for them so they don't all promote them very actively---
Example: Recently in early 2017 CNI released a DPSS MGL-F-577nm lab lasers which they determined there was a market for - see:
577 nm Yellow Laser, Solid State Laser, Yellow Laser Module | CNIlaser
and for many years prior 556, 561, 589nm and 593.5nm see:
Yellow laser, 593.5/556/561/589 nm DPSS yellow laser, orange laser system.