How do these other colored lasers function?

[solar00]

I was wondering how these other colored lasers actually work.

Red is just a red diode with a lens,  green is 808nm diode + a set of crystals to create 532nm.
And i guess yellow is just a combination of red and green.

But how is this blue light from laserpointers actually created and why is the ouput power so much lower?
Is purple/violet also created in the same way as the blue ones?

Finally if you want to create a white laser, does the red,green and blue need to be exactly the same power or do you need more red and blue than green (because green is more visible)

 

[SenKat]

Solar, although I am certian someone will reply (and soon) with some of the answers for you - the rest is all on the forum for the finding ! Blu-ray is a bare diode, like red and IR - the blue, yellow, orange, and green are all made from crystals being pumped by an IR diode, and some of the more exotic colors are only created by luck of the draw, since they are so unstable ! The efficeincy of the crystals goes WAY down when it comes to yellow or blue - but for more in depth explanation - take a peek around the "other colored lasers" threads...LOTS of info there

G !

 

[pseudonomen137]

Well, it really depends because you can make different colors via different methods. For instance, red lasers are commonly made with bare diodes and a lens, but you can also get gas lasers like HeNe and Krypton to make red, as well as DPSS (just like creating a greenie) and other processes.

A true yellow laser cannot be an RG combo. 593.5nm can be made via a DPSS process like green, 594.1nm HeNes exist, and there are many other wavelengths achievable by gas/DPSS lasers, as well as tuneable dye lasers. Not to mention we may see yellow laser diodes someday.

If you only care about getting the color yellow though, like in lasershows, combining red+green is far cheaper and is good enough.

Blue is commonly achieved by 473nm DPSS like a greenie (but much more difficult/inefficiently, hence the high prices for lower powers), and argon gas lasers which lase at 488nm, as well as some other blue lines. more recently we're also seeing 440nm blue diodes.

Violet 405nm diodes came about recently for blu-ray/hd-dvd, as well as various gas and DPSS processes in the UV range.


For a whitelight laser you can combine red/green/blue, but the proportions are not equal and are based on many variables. First off, different wavelengths of red and blue affect proportions. Sometimes you'll even see more 635nm used than 532nm, whereas with something like 671nm, you'll always need less green. The wavelength not only affects the apparent visibility, but how deep that color is. Additionally, the proportions change as the combined output power does, so its a tough question to answer generally (although a lot of people like to quote a 4 red : 2 blue : 1 green ratio for a very rough white balance).

 

[Things]

blue/UV lasers aren't nessesary lower powered, but it is just that you need really high powered pump diodes. a blu ray diode can be up to even 20mw! that is why blue is so expensive, you need much higher powered pump diodes to get a small amount of blue, same with yellow. pseudo pretty much said it all!

 

[solar00]

Thanks for the info,

So creating these colors is a little more complicated than i thought.
That explains why lasers other than red and green are so expensive (in $ per mw)

 

[BlueFusion]

yep

 

[Thories]

im hoping laser tv and all those implications will make RGB lasers cheap as chips. its all about supply and demand really.